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Magnetostriction: Theory and Applications of Magnetoelasticity
... Thus, the investigation on magnetic transition and transition temperature is significant in understanding magnetic properties and phenomena. In fact, due to the interaction between magnetic moment and lattice strain, which has a quantum mechanical origin and exists in all magnetic systems, magnetic materials can also demonstrate a magneto-elastic effect [3,4]. Since the moments of the rare-earth elements and the cobalt are antiparallel, the Laves-phase intermetallic RT 2 compounds (R, rare-earth element; T, transition metal element, Fe/Co/Ni) are ferrimagnetic below Curie temperature (T C ) [1,5]. ...
... According to the mechanism of magnetostriction described in Figure 1, the crystal in the tetragonal phase (c/a < 1) yields negative thermal expansion and negative magnetostriction, but it seems to contradict the experimental results in Figure 3(e, h) because both the thermal expansion and the saturated magnetostriction are positive. This is attributed to the two steps involved in the magnetization/magnetostriction process for polycrystalline samples, domain switching, and domain rotation [3,28]. For simplicity, Figure 1 depicts only the domain switching but not domain rotation. ...
... As for soft magnets, the magnetic field required for complete domain switching is usually not high (approximately 1000 Oe for Tb0.3Dy0.7Co2 at 90 K); if the field increases further, domain rotation would happen, and it is possible to alter the value of the finally measured magnetostriction. Therefore, it is understandable that when the magnetic field exceeds 1000 Oe, which is required for domain switching of Tb0.3Dy0.7Co2, the magnetostriction changes from negative to positive, and such a phenomenon is not rare in magnetostrictive materials [2,3,7,28]. Despite the polycrystalline state, the samples are applied with the magnetic field above T C and the subtraction curve of the 1 Tesla and 0 Tesla are utilized to study the thermal expansion effect, so the non-magnetic thermal expansion (caused by temperature variation) is not considered here [11]. ...
The magneto-elastic coupling effect correlates to the changes of moment and lattice upon magnetic phase transition. Here, we report that, in the pseudo-binary Laves-phase Tb1-xDy
x
Co2 system (x = 0.0, 0.7, and 1.0), thermal expansion and magnetostriction can probe the ferrimagnetic transitions from cubic to rhombohedral phase (in TbCo2), from cubic to tetragonal phase (in DyCo2), and from cubic to rhombohedral then to tetragonal phase (in Tb0
.
3Dy0.7Co2). Furthermore, a Landau polynomial approach is employed to qualitatively investigate the thermal expansion upon the paramagnetic (cubic) to ferrimagnetic (rhombohedral or tetragonal) transition, and the calculated thermal expansion curves agree with the experimental curves. Our work illustrates the correlation between crystal symmetry, magnetostriction, and thermal expansion in ferrimagnetic Laves-phase alloys and provides a new perspective to investigate ferrimagnetic transitions.
... Case II: Targets are bound at the free end of a cantilever [10]. ...
... Moreover, a/l for the maximal sensitivity shifts to the fixed end as the resonance order increases as shown in Figure 6. It is found that the data curve can be fitted well by an exponent decaying function as follows (10) where y0 = 0.05842, A = 21.72383, c = 1.62126 × 10 −4 ; x represents a/l. ...
... c = 1.62126 × 10 −4 ; x represents a/l. Therefore, a/l corresponding to the maximal sensitivity of the cantilever under higher order resonances can be predicted, based on Equation (10). Moreover, a/l for the maximal sensitivity shifts to the fixed end as the resonance order increases as shown in Figure 6. ...
We derived an analytical expression for a resonant-mode based bi-layered cantilever with distributed mass load. The behavior of mode of vibration, nodal position, frequency shift, as well as sensitivity under different mass load distributions was theoretically studied. The theoretical results suggested that asymmetric mass load distribution leads to the shift of nodes as well as the sensitive regions of a resonant-mode based cantilever. n − 1 local maximal sensitivities and n − 1 local minimal sensitivities are observed when the cantilever vibrates in the nth-order resonance. The maximal sensitivity is found at the first local maximal sensitivity and the behavior of mass load length as a function of the maximal sensitivity follows the rule of an exponent decaying function. The sensitivity increases as the load mass increases for the same mass load distribution, but the corresponding slopes are different.
... Applying strain is a gripping handle for controlling magnetic excitations. Magnetostriction is very common in magnetic materials [25]. In antiferromagnets, a strain can also couple to the Neel vector through the linear magnetoelastic coupling [26,27]. ...
... This can also be achieved by performing a pulse measurement and detect the voltage obtained with the two possible polarities of the externally applied magnetic field. Thus we construct the two following signals : 25.a and b. It is important to notice that the part that is even with respect to the magnetic field polarity ( †) is odd with respect to the current polarity, while the part that is odd with respect to the magnetic field polarity () is even with respect to the current polarity. ...
The generation and detection of pure spin currents circulating in magnetic insulator materials are at the heart of insulating spintronics. It have proven its worth by enabling transport of spin information across large distances, much further than in metals, thanks to the absence of decay mechanism through the delocalized electrons. Spin currents here propagate over localized magnetic moments via spin-waves (SW), or their quanta the magnons, with characteristic frequencies ranging from GHz to THz and associated wavelengths from µm to nm. Recently, considerable attention in the field of insulating spintronics has been given Yttrium Iron garnets (YIG), which is a ferrimagnetic insulator with the lowest known amount of magnetic damping. My thesis work focuses on spin waves transport in high-quality ultra-thin films exploiting spin-orbit tools to interconvert the spin signal into an electrical signal. By injecting a high current density in Pt electrodes deposited few microns apart on top of a YIG film, a pure magnon current propagating in the YIG can be induced/detected via the direct/inverse spin Hall effect. The main contribution of my work is a wide investigating of the spin transfer at large energies. We have found that the spin conductance in this system can cross several regimes that involve a strong change in the magnon distribution. Throughout various techniques such as Brillouin light scattering spectroscopy, spin Seebeck and spin Hall magnetoresistance measurements, we provide a complete analysis of the different phenomena surrounding the spin transport at large energy in thin YIG films and we will show that our experimental findings do not support yet the emergence of the new collective behaviors, such as Bose-Einstein condensation at room temperature.
... We demonstrate its performance in generating sound pressure in a standard 2 ccm measurement volume. The main advantages of magnetostriction compared to other actuation principles are the high energy density, short reaction times and contactless operation as well as the possibility of low driving voltages due to low actuator impedances [11,12,13,14]. ...
... More extensive treatment of magnetostrictive effects can be found in literature [11,12,13,14]. ...
... (2) Magnetostrictive mechanism Specifically, there are three reasons to change the magnetization state of the ferromagnetic material by changing the shape and volume of ferromagnetic materials [18,19]. The main effect of magnetostrictive strain on giant magnetostrictive material is field-induced deformation [20]. 1 Spontaneous deformation caused by spontaneous magnetization Spontaneous magnetization is caused by an exchange force independent of the external magnetic field. ...
... When the transition occurs, the set of times τ(t) can be expressed by Equation (18). ...
Giant magnetostrictive actuators (GMA) driven by giant magnetostrictive material (GMM) has some advantages such as a large strain, high precision, large driving force, fast response, high reliability, and so on, and it has become the research hotspot in the field of microdrives. Research shows there is a nonlinear, intrinsic relationship between the output signal and the input signal of giant magnetostrictive actuators because of the strong coupling characteristics between the machine, electromagnetic field, and heat. It is very complicated to construct its nonlinear eigenmodel, and it is the basis of the practical process of giant magnetostrictive material to construct its nonlinear eigenmodel. Aiming at the design of giant magnetostrictive actuators, the magnetization model based on a free-energy hysteresis model has been deeply researched, constructed, and put forward by Smith, which combines Helmholtz–Gibbs free energy and statistical distribution theory, to simulate the hysteresis model at medium or high driving strengths. Its main input and output parameters include magnetic field strength, magnetization, and mechanical strain. Then, numerical realization and verification of the magnetization model are done by the Gauss–Legendre integral discretization method. The results show that the magnetization model and its numerical method are correct, and the research results provide a theoretical basis for the engineering application of giant magnetostrictive material and optimized structure of giant magnetostrictive material actuators, which have an important practical application value.
... In this section we describe only those magneto-elastic affects which are related to our work, namely the connection between hydrostatic pressure and lattice geometry, the definition of the bulk modulus and the effect of pressure on magnetic moment. For all other magneto-elastic effects the interested reader is referred to literature [15,16]. ...
... The bulk modulus [15][16][17][18][19] of a substance measures the substance's resistance to uniform compression. It is defined as the pressure increment needed to cause a given relative decrease in volume. ...
... The metallic glasses of the present study show excellent coupling between magnetic and elastic properties, that is, the applied mechanical stress and the magnetic field generating equivalent effects in the magnetization and deformation of the materials. A direct consequence of the magnetoelastic coupling is the dependence of the elastic constants of magnetostrictive materials on the external magnetic field , in particular the dependence of the longitudinal Young's modulus on , known as the effect ( = 1 − ( )/ , with being the Young's modulus measured at magnetic saturation (a detailed mathematical formula can be found in [21]). ...
... The metallic glasses of the present study show excellent coupling between magnetic and elastic properties, that is, the applied mechanical stress and the magnetic field generating equivalent effects in the magnetization and deformation of the materials. A direct consequence of the magnetoelastic coupling is the dependence of the elastic constants of magnetostrictive materials on the external magnetic field H, in particular the dependence of the longitudinal Young's modulus on H, known as the ∆E effect (∆E = 1 − E(H)/E S , with E S being the Young's modulus measured at magnetic saturation (a detailed mathematical formula can be found in [21]). ...
The main parameters of magnetoelastic resonators in the detection of chemical (i.e., salts, gases, etc.) or biological (i.e., bacteria, phages, etc.) agents are the sensitivity S (or external agent change magnitude per Hz change in the resonance frequency) and the quality factor Q of the resonance. We present an extensive study on the experimental determination of the Q factor in such magnetoelastic resonant platforms, using three different strategies: (a) analyzing the real and imaginary components of the susceptibility at resonance; (b) numerical fitting of the modulus of the susceptibility; (c) using an exact mathematical expression for the real part of the susceptibility. Q values obtained by the three methods are analyzed and discussed, aiming to establish the most adequate one to accurately determine the quality factor of the magnetoelastic resonance.
... The useful information expected by engineers and technicians is the magnetostriction curve, as plotted in Figure 1, which characterizes the magnetostrictive material [4]. Indeed, one could easily define the maximum of deformation and estimate λ s which is usually reported by the manufacturer in the literature. ...
... We report magnetostriction curve under preload ( Figure 4): it appears different curves and in particular, the maximum slope of the curves reported are 15, 80, and 40 10 À9 A/m for pressures of 0, 20, and 40 MPa, respectively. Such values are greater than those predicted by du Trémolet de Lacheisserie [4]. ...
... These last properties can be monitored by an applied controlled stress by various methods, for example in situ mechanical tests using a tensile module combined with magnetic force microscopy (MFM) to image the magnetic domains [19] or with Brillouin light scattering (BLS) technique [23] to follow the spin waves behavior, of NiFe films as function of the applied stress. These changes can be understood through magnetoelastic coupling [25]. Magnetic properties of thin films are also sensitive to surface roughness [26][27][28][29][30][31][32]. ...
... This is evidenced on hysteresis loops characterized by their coercivity and squareness. The coupling between strain and magnetic anisotropy is widely described in Ref [25]. However, it has been shown that the Young's modulus is not easy to measure in thin films [34,35]. ...
... These are multi-functional materials with magnetostrictive and piezoelectric phases. The mechanism of strain driven magnetic properties in ExMF relies on the strain being transferred to the magnetostrictive phase and, in turn, induces inverse magnetostriction (the Villari effect 12 ), which translates into a change in magnetic properties. Thus, understanding and controlling the magnetic properties through strain in these multiferroics are of great interest for energy efficient applied issues [3][4][5][6][13][14][15][16][17][18][19][20][21][22][23][24] . ...
Using strain to control magnetic properties through anisotropy changes is a method to create functional materials with energy efficient applications. The strain can be inferred remotely by the light-induced non-thermal dimension change of materials named the photostrictive effect. Still, the control of dynamic magnetic properties via this effect is pursued. The need of a physical quantity to encompass and to describe anisotropic magnetization changes under the photostrictive effect is also remaining. Here, the photostrictive effect with visible light is used to engineer static and dynamic magnetic properties in a multiferroic material. A converse magneto-photostrictive coupling coefficient is also proposed as a physical quantity to assess anisotropic magnetization changes under this effect. These results provide a path towards understanding light-induced magnetization changes and a potential to be used in wireless approaches for the control of magnetic properties and tunable RF/microwave devices.
... Although magnetoelastic effects have been thoroughly investigated for over 100 years [3], the generalized model of magneto-mechanical interactions has not yet been presented. The recently-published analyses indicate that the comprehensive explanations of the physical mechanisms behind the magnetoelastic effect require analyses involving the quantum physics of solid state [4]. ...
Measurements of mechanical stress dependence of magnetic properties of electrical steels are significant from both theoretical and application points of view. The paper presents a novel measuring setup for testing the magnetoelastic properties of electrical transformer sheets made of grain-oriented and non-grain-oriented steel. The proposed method takes into consideration the angle between the easy electrical steel magnetization axis and the mechanical stress direction. Due to the innovative 3D self-adjustment mechanism of the yoke position, measurements may be taken for different magnetization strengths and angles. The paper also presents detailed uncertainty analyses and examples of results of magnetoelastic measurements for grain-oriented electrical steel M120-27s. The presented results validate the method and confirm its usability for further detailed studies of mechanical stress dependence of magnetic properties of electrical steels.
... Besides graphene, other 2D materials have also seen applications in NEMS for their unique mechanical, electrical, and optical properties with different degrees of freedom, such as optical properties and charge density wave transitions of transition-metal dichalcogenides [10][11][12] and magnetic phase transitions in antiferromagnetic/ferromagnetic materials 13 . Recently, the field-induced magnetostriction [14][15][16] in an antiferromagnetic 2D material has been used to develop new control of magneto-mechanical coupling in the context of NEMS 17 . ...
The antiferromagnetic topological insulator MnBi2Te4 (MBT) exhibits an ideal platform to study exotic topological phenomena and magnetic properties. The transport signatures of magnetic phase transitions in the MBT family materials have been well-studied. However, their mechanical properties and magneto-mechanical coupling have not been well-explored. We use nanoelectromechanical systems to study the intrinsic magnetism in MBT thin flakes via their magnetostrictive coupling. We investigate mechanical resonance signatures of magnetic phase transitions from antiferromagnetic (AFM) to canted antiferromagnetic (cAFM) to ferromagnetic (FM) phases versus magnetic field at different temperatures. The spin-flop transitions in MBT are revealed by frequency shifts of mechanical resonance. With temperatures going above TN, the transitions disappear in the resonance frequency map, consistent with transport measurements. We use a magnetostrictive model to correlate the frequency shifts with the spin-canting states. Our work demonstrates a technique to study magnetic phase transitions, magnetization and magnetoelastic properties of the magnetic topological insulator.
... Using symmetry conditions of the respective magnetic system, b can be simplified and reduced to, e.g., two independent components for cubic symmetry and one for isotropic symmetry. A collection of formulations for various symmetries can be found in [352]. All materials used in this thesis are magnetoelastically isotropic and can be described by [323] ...
Many conceivable biomedical and diagnostic applications require the detection of small-amplitude and low-frequency magnetic fields. Against this background, a magnetometer concept is investigated in this work based on the magnetoelastic ΔE effect. The ΔE effect causes the resonance frequency of a magnetoelastic resonator to detune in the presence of a magnetic field, which can be read-out electrically with an additional piezoelectric phase. Various microelectromechanical resonators are experimentally analyzed in terms of the ΔE effect and signal-and-noise response. This response is highly complex because of the anisotropic and nonlinear coupled magnetic, mechanical, and electrical properties. Models are developed and extended where necessary to gain insights into the potentials and limits accompanying sensor design and operating parameters. Beyond the material and geometry parameters, we analyze the effect of different resonance modes, spatial property variations, and operating frequencies on sensitivity. Although a large ΔE effect is confirmed in the shear modulus, the sensitivity of classical cantilever resonators does not benefit from this effect. An approach utilizing surface acoustic shear-waves provides a solution and can detect small signals over a large bandwidth. Comprehensive analyses of the quality factor and piezoelectric material parameters indicate methods to increase sensitivity and signal-to-noise ratio significantly. The latter is currently limited by the loss of the magnetic material. First exchange-biased ΔE-effect sensors pave the way for compact setups and arrays with a large number of sensor elements. With a signal-and-noise model extended to sensor arrays, specific requirements are identified that could improve the signal-to-noise ratio. The insights gained lead to a new resonator and processing concept that can circumvent several previous limitations. With the obtained results and developed models, important contributions are made to the understanding and development of ΔE-effect magnetometers with prospects for sensor improvements in the future.
... see Reyne et al., 1987). They foremost expand when applied a magnetic field, a phenomenon called magnetostriction (Joule, 1847;Lee, 1955;Du Trémolet De Lacheisserie, 1993). More recently, interest in computing stresses in electric motors also arose for questions of motor performance, as the magnetostriction effect is accompanied by it reverse phenomena, referred to as inverse magnetostriction or Villari effect: stresses in ferromagnetic materials stretch and reorient the magnetic domains within the material. ...
>>> Link : https://www.theses.fr/2021IPPAX015 <<<
Future developments of lighter, more compact and powerful motors -- driven by environmental and sustainability considerations in the transportation industry – involve higher stresses, currents and electromagnetic fields. For the components used in electric motors – especially for the ferromagnetic ones – strong couplings between mechanical, thermal and electromagnetic effects arise, which are amplified by the higher loads. They affect the machine’s performance, thus requiring a consistent multiphysics modeling for the motors’ design. Understanding and modeling these couplings has recently become an important subject of research. The work presented here proposes a coupled electromagnetic-thermomechanical continuum theory together with analytical and numerical (finite element) tools for the solutions of boundary value problems arising in electric motors.In the first part of the work, using the direct approach of continuum mechanics, based on a Eulerian (current configuration) approach, a general modeling framework coupling the electromagnetic, thermal and mechanical fields is derived from the basic principles of thermodynamics using the eddy current approximation. Although the proposed theory is general enough to account for a wide range of material behaviors, particular attention is paid to the derivation of the coupled constitutive equations for isotropic materials under small strain but arbitrary magnetization. As a first application, the theory is employed for the analytical modeling of the rotor and stator of idealized electric motor configurations for which we calculate the electric current, magnetic, stress and temperature fields. At the rotor, the different components of the stress tensor and body force vector are compared to their purely mechanical counterparts due to inertia, quantifying the significant influence of electromagnetic phenomena. At the stator, comparison with coarser models found in the electrical engineering literature is provided, quantifying the influence of the proposed model on the elastic stress and strains’ amplitudes.In the second part of the work, a variational formulation of the problem is presented based on a Lagrangian (reference configuration) approach and shown to be equivalent to the direct approach. The numerical implementation of the proposed model – via a user element in a general purpose finite element code and accounting for non-linear material behavior – is validated by comparison of the results from the analytical models of the simplified stator configuration to the numerical results for small values of the magnetic field (range of linear behavior for the magnetic field). Calculations are then performed on more complex stator configurations with a more intense magnetic field, using a non-linear magnetic response that accounts for magnetic saturation (a Langevin-type model), in order to put forward the capacities of the proposed formulation and obtain results for realistic engineering applications.
... Магнитные материалы, такие как Fe-Ga (Галфенол), демонстрируют большую магнитострикцию в слабых магнитных полях и могут быть использованы в качестве акустических сенсоров, преобразователей, генераторов, линейных индукторных двигателей, актуаторов, демпфирующих устройств, датчиков крутящего момента, позиционных устройств, динамиков, микрофонов, и т.д. Кроме того, себестоимость Галфенола значительно ниже в сравнении с другими магнито-стрикционными материалами, такими как Терфенол-D [2][3][4][5]. Величина магнитострикции в Fe-Ga сплавах зависит от способа их термообработки [6,7] и кристаллографической текстуры [8,9]. Вследствие анизотропии магнитострикционных свойств Fe-Ga-сплавов имеется значительное различие между проявлениями их магнитострикции вдоль различных кристаллографических осей: направление k100l в монокристаллах отличают максимальные значения магнитострикции, тогда как для k111l направлений характерен их минимум. ...
... Magnetostriction, which refers to the change in shape or dimension in response to a magnetic field, is one of the inherent properties of magnetic materials that was firstly discovered in 1842 by J. P. Joule in Fe [1,2]. These magnetic materials can be applied as sensors, actuators, and energy harvesting devices because the magnetostrictive response allows these ferromagnetic materials to convert electromagnetic energy to mechanical energy. ...
In the present work, the microstructure and its effect on the magnetic, magnetocaloric, and magnetoelastic properties of the Tb55Co30Fe15 melt-spun ribbon were investigated. The ribbon exhibits typical amorphous characteristics in its X-ray diffraction examination and differential scanning calorimetry measurement. However, the magnetic properties of the ribbon indicate that the ribbon is inhomogeneous in the nanoscale, as ascertained by a high-resolution electron microscope. Compared to the Tb55Co45 amorphous alloy, the Tb55Co30Fe15 ribbon shows poor magnetocaloric properties but outstanding magnetostriction. A rather high value of reversible magnetostriction up to 788 ppm under 5 T was obtained. The mechanism for the formation of nanoparticles and its effect on the magnetocaloric and magnetostrictive properties were investigated.
... One way to overcome these limitations is by using a modulation scheme based on the delta-E effect. The delta-E effect is the change of the effective elastic properties with magnetization due to magnetoelastic coupling [5][6][7][8]. It results from inverse magnetostriction that adds additional stress-induced magnetostrictive strain to the purely elastic Hookean strain. ...
Magnetoelectric resonators have been studied for the detection of small amplitude and low frequency magnetic fields via the delta-E effect, mainly in fundamental bending or bulk resonance modes. Here, we present an experimental and theoretical investigation of magnetoelectric thin-film cantilevers that can be operated in bending modes (BMs) and torsion modes (TMs) as a magnetic field sensor. A magnetoelastic macrospin model is combined with an electromechanical finite element model and a general description of the delta-E effect of all stiffness tensor components Cij is derived. Simulations confirm quantitatively that the delta-E effect of the C66 component has the promising potential of significantly increasing the magnetic sensitivity and the maximum normalized frequency change ∆. However, the electrical excitation of TMs remains challenging and is found to significantly diminish the gain in sensitivity. Experiments reveal the dependency of the sensitivity and ∆ of TMs on the mode number, which differs fundamentally from BMs and is well explained by our model. Because the contribution of C11 to the TMs increases with the mode number , the first-order TM yields the highest magnetic sensitivity. Overall, general insights are gained for the design of high-sensitivity delta-E effect sensors, as well as for frequency tunable devices based on the delta-E effect.
... Hard ferrites are powders that are Ba or Sr based, with compositions reaching a remanent magnetization of 0.4 T. Final composition magnetic properties are weaker than powder fillers and can be further modified by secondary structure modification in design shape. Supplementary additives and coupling agents modify the surface properties of filler particles and improve interface compatibility with the matrix [46][47][48][49]. ...
In this paper is proposed a dynamic torque, rotational speed, and shaft position sensor. It is built of magnetic elastomer coating directly applied over a rotating shaft. The sensor is used for precise measurements of changes in torque and speed, and it is usable at high rotational speeds, directly on the device shaft. The sensor is based on magnetic elastomer material deformation and the corresponding change in magnetic field amplitude and direction. The proposed sensor design is simple and can acquire reliable readings for a wide range of rotational speeds. Sensor design consists of the following: magnetic elastomer coating with nanoparticles, in which, elastomer is used for a sensing convertor; magneto-resistive linear field sensor; and microprocessor unit for calibration and control. Numerical and experimental test results are demonstrated and analyzed. Sensor implementation aims to meet magnetic mechatronic systems’ specific requirements.
... Yet classical in linear theories, constitutive tensors are also encountered in non-linear mechanics of materials such as, for instance, anisotropic elasto-plasticity (e.g. Hill yield tensor [43]), in continuum damage mechanics (for a description of damage anisotropy see [20,19,67,55,47,56]) and in nonlinear piezoelectricity/magnetism (e.g. the magnetostriction morphic tensor [31,44]). ...
We produce minimal integrity bases for both isotropic and hemitropic invariant algebras (and more generally covariant algebras) of most common bidimensional constitutive tensors and -- possibly coupled -- laws, including piezoelectricity law, photoelasticity, Eshelby and elasticity tensors, complex viscoelasticity tensor, Hill elasto-plasticity, and (totally symmetric) fabric tensors up to twelfth-order. The concept of covariant, which extends that of invariant is explained and motivated. It appears to be much more useful for applications. All the tools required to obtain these results are explained in detail and a cleaning algorithm is formulated to achieve minimality in the isotropic case. The invariants and covariants are first expressed in complex forms and then in tensorial forms, thanks to explicit translation formulas which are provided. The proposed approach also applies to any $n$-uplet of bidimensional constitutive tensors.
... The smart structure system has the capability to perform self-diagnosis and adjust to the environment alteration. Joule [1], Mccombe et al. [2] and De Lacheisserie [3] considered the magnetostrictive material as one of smart materials that change dimensions as response to stresses when exposed to magnetic field. These materials are appropriate for providing giant forces, j m a t e r r e s t e c h n o l . 2 0 2 0;x x x(x x):xxx-xxx strains, high energy densities, noise and vibration control more for heavy structures as mentioned in Dapino [4] and Liu et al. [5]. ...
Vibration suppression analysis of a laminated composite plate embedded magnetostrictive layers is presented with/without the transverse shear and normal strains effects are taken into account in this study. For purpose of vibration suppression, the velocity feedback control with constant gain distributed is applied. The formulation of problem is written to give five theories are Euler-Bernoulli’s classical plate theory, the Timoshenko’s first-order and Reddy’s third-order shear deformation plate theories, simple and refined sinusoidal shear deformation plate theories and other theories. The governing equations of motion are obtained using the Hamilton’s principle. Navier’s method is applied to discuss the solution of vibration problem at the simply-supported boundary conditions. Some effects are extensively studied and discussed such the impact of material properties, modes, thickness and number of the magnetostrictive layers, lamination schemes, magnitude of the feedback coefficient and location of the magnetostrictive layers on vibration suppression of the system. Numerical results are reported and illustrated, and various conclusions are formulated.
... 另外, 众所周知, 材料的微观结 构和力学性能也可以通过磁化来改变. 在磁场下, 由于 磁化过程和应变的相互作用, 样品中会出现体磁致伸 缩、Joule磁致伸缩、Weidemann和ΔE效应等 [7,8] . 数十 效应 [9][10][11][12] . ...
In this paper, the interaction between magnetization and dynamic relaxation of heterogeneous structure in a
ferromagnetic metallic glass (MG) is investigated. It is found that the magnetic state of the MG can be changed through
wearing its surface. Accompanying with the change of magnetic state, the local dynamic mechanical behavior of the MG
detected by nanoindentation varies. Through analyzing with combination of the three-parameter viscoelastic model and
state-transition theory, it is discovered that the microstructure of the glass can be apparently changed by magnetization
with the effective size, viscosity of the liquid-like cores and the relaxation time increased by more than 3 times. Inversely,
with cycling loading below the elastic limit of the MG using nanoindentation, it is revealed that localized flows of nanoliquid
in the glass erase the effect of magnetization. The interaction between magnetization and localized flows relates to
spin-orbit coupling in the MG; the change of magnetic state and liquid-like regions in the MG does not affect its
instantaneous shear modulus associated with its ideal glassy state. The studies help understand the dynamic magnetomechanical
properties of amorphous magnetic materials, and have technological importance for their applications.
... The composition of the alloys can be modulated in order to look for some specific applications or characteristics of the resonant sensing platform. To fabricate such ribbons in the amorphous phase, which is a metastable state, the composition must be 70 − 80% of metallic elements (Fe, Ni, Co, Cr, Au) and include a 30-20% of metalloids (B, C, Si, P, etc., which favors the formation of the amorphous phase) [10,11]. It has been observed that Fe-rich amorphous alloys show high strength and hardness, presenting also good magnetic and magnetoelastic properties, low material costs and a superior corrosion resistance, being thus of critical importance for the desired application of the ribbons. ...
We have performed a study of the magnetic, magnetoelastic, and corrosion resistance properties of seven different composition magnetoelastic-resonant platforms. For some applications, such as structural health monitoring, these materials must have not only good magnetomechanical properties, but also a high corrosion resistance. In the fabricated metallic glasses of composition Fe(73-x)NixCr5Si10B12, the Fe/Ni ratio was varied (Fe + Ni = 73% at.) thus changing the magnetic and magnetoelastic properties. A small amount of chromium (Cr5) was added in order to achieve the desired good corrosion resistance. As expected, all the studied properties change with the composition of the samples. Alloys containing a higher amount of Ni than Fe do not show magnetic behavior at room temperature, while iron-rich alloys have demonstrated not only good magnetic properties, but also good magnetoelastic ones, with magnetoelastic coupling coefficient as high as 0.41 for x=0 in the Fe73Ni0Cr5Si10B12 (the sample containing only Fe but not Ni). Concerning corrosion resistance, we have found a continuous degradation of these properties as the Ni content increases in the composition. Thus, the corrosion potential decreases monotonously from 46.74 mV for the x=0 composition, Fe73Ni0Cr5Si10B12 to -239.47 mV for the x=73 composition Fe0Ni73Cr5Si10B12.
... The magnetoelastic effect in ferromagnetic materials is of crucial interest to practitioners interested in exploring new possibilities for development of novel sensors and high-performance machines [1][2][3][4][5]. From the historical perspective, the magnetostriction effect, i.e., the change in shape of a ferromagnetic body under the action of external magnetic field, was one of the oldest coupled phenomena studied already by J. P. Joule in 1842 [6]. ...
A novel approach to take into account the effect of compaction pressure on the shape of modeled hysteresis curves of self-developed soft magnetic composite cores is presented. The description relies on the introduction of an additional term in the so-called effective field, which is assumed proportional to the compaction pressure. The proposed model bears some resemblance to the Sablik's extension of the Jiles-Atherton model, readily used in the studies of the magnetoelastic effect. Verification of the description is carried out using measurement data from self-developed iron-based composite cores.
... The composition of the alloys can be modulated in order to look for some specific applications or characteristics of the resonant sensing platform. To fabricate such ribbons in the amorphous phase, which is a metastable state, the composition must be 70 − 80% of metallic elements (Fe, Ni, Co, Cr, Au) and include a 30-20% of metalloids (B, C, Si, P, etc., which favors the formation of the amorphous phase) [10,11]. It has been observed that Fe-rich amorphous alloys show high strength and hardness, presenting also good magnetic and magnetoelastic properties, low material costs and a superior corrosion resistance, being thus of critical importance for the desired application of the ribbons. ...
We have performed a study of the magnetic, magnetoelastic, and corrosion resistance properties of seven different composition magnetoelastic-resonant platforms. For some applications, such as structural health monitoring, these materials must have not only good magnetomechanical properties, but also a high corrosion resistance. In the fabricated metallic glasses of composition Fe73-xNixCr5Si10B12, the Fe/Ni ratio was varied (Fe+Ni=73% at.) thus changing the magnetic and magnetoelastic properties. A small amount of chromium (Cr5) was added in order to achieve the desired good corrosion resistance. As expected, all the studied properties change with the composition of the samples. Alloys containing a higher amount of Ni than Fe do not show magnetic behavior at room temperature, while iron-rich alloys have demonstrated not only good magnetic properties, but also good magnetoelastic ones, with magnetoelastic coupling coefficient as high as 0.41 for x=0 in the Fe73Ni0Cr5Si10B12 (the sample containing only Fe but not Ni). Concerning corrosion resistance, we have found a continuous degradation of these properties as the Ni content increases in the composition. Thus, the corrosion potential decreases monotonously from 46.74 mV for the x=0, composition Fe73Ni0Cr5Si10B12 to −239.47 mV for the x=73, composition Fe0Ni73Cr5Si10B12.
... The magnetoelastic effect in ferromagnetic materials is of crucial interest to practitioners interested in exploring new possibilities for development of novel sensors and high-performance machines [1][2][3][4][5]. From the historical perspective, the magnetostriction effect, i.e., the change in shape of a ferromagnetic body under the action of external magnetic field, was one of the oldest coupled phenomena studied already by J. P. Joule in 1842 [6]. ...
Magnetic properties of soft magnetic composites are highly sensitive to the processing conditions. In this paper we focus on the possibility to model this effect using the Jiles-Atherton-Sablik theory. It is assumed that the effect of varying compaction pressure may be described by direct introduction of stress-dependent term in the model equations. The values of model parameters are kept constant. Verification of the proposed approach is carried out using measurement data from self-developed iron-based composite cores.
... Research [8,[11][12][13] shows the following points: There is a nonlinear eigen relation between the output signal and the input signal of the GMA. It is a major problem in the practical application of intelligent materials for its intrinsic nonlinearity. ...
A giant magnetostrictive actuator presents advantages such as large strain, high precision, and quick response. It is a hotly debated research topic in the field of micro drivers; however, the nonlinear intrinsic relationship between its output and input signals make it difficult to construct its nonlinear eigen model in the process of its practical application. Therefore, the motivation of this paper is to study the nonlinear magnetic–mechanical coupling characteristics of the giant magnetostrictive actuator, which is driven by free energy hysteresis characteristics. The nonlinear magnetic–mechanical coupling model under the weak form solution is deduced from the basic electromagnetic and mechanical theories, based on the distribution law of the axial magnetic field simulation, carried out to analyze the output displacement characteristics of the giant magnetostrictive actuator under preload. Experimental characterization of the device is also studied in the built experiment setup. Research results show that the experimental results coincide well with the simulation results, which show that the designed magnetic circuit for the giant magnetostrictive actuator is correct, and the coupling model of magnetic and machine of the giant magnetostrictive actuator based on the free energy hysteresis characteristics is reasonable.
... In magnetoelectric laminated composites, the magnetoelectric effect is due to the magnetic-mechanical-electric transform, induced by the mechanical coupling between a magnetostrictive and a piezoelectric layer. To enable the piezomagnetic behavior of the magnetostrictive material, the magnetic layer needs to be polarized by a DC magnetic field with a superimposed AC field [1]. ...
In this paper, we report the fabrication of a rare-earth free current sensor based on a PZT/NiCoZn-ferrite magnetoelectric (ME) trilayer composite disk. To improve the sensitivity of the sensor, the structure uses an in-plane series connection, which increases the ME voltage by two for a fixed volume. Then, we propose a full characterization of the sensor: electrical modeling, low and high frequency limits, sensitivity, linearity, distortion and resolution. The device is also evaluated under sinus, square, and triangle waveform currents, which are excitation signals commonly used in the field of electrical engineering. The current sensor shows high current sensitivity (90 mV/A), good linearity from 0.001 to 30 A and low added impedance (0.01 Ω) in a frequency range of 10 Hz–30 kHz for a very compact structure (4 cm³). It also exhibits a high resolution of 1 mA (for a 1 A peak signal) and good stability. © 2018 Springer Science+Business Media, LLC, part of Springer Nature
... Magnetostrictive materials play an increasingly important role in applications ranging from active vibration control, controlled surface deployment, actuators, damping devices, linear motors, positioning devices, and energy harvesting to stress and torque sensing [1,2]. In materials science, galfenol [3] is the general term for an alloy of iron and gallium. ...
In this work, photostrictive manipulations of static and dynamic magnetic properties are demonstrated in an extrinsic multiferroic composite. The photostriction is achieved with visible light in the blue region of the spectrum. The composites consist of 5 nm or 10 nm magnetostrictive Fe$_{81}$Ga$_{19}$ thin films coupled to a piezoelectric (011)-Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$-Pb(Zr,Ti)O$_3$ substrate. Angular dependent magnetization reversals properties are largely enhanced or reduced under a converse magneto-photostrictive effect (CMPE). The CMPE strength is analysed with a novel coefficient named the converse magneto-photostrictive coupling coefficient. This coefficient is proposed as a general approach to analyse and to compare different extrinsic multiferroics under the converse magneto-photostrictive effect. Its thickness dependence reveals that the CMPE strength decreases with an increase of the Fe$_{81}$Ga$_{19}$ thickness. Experimental evidence for a control of dynamic magnetic properties under CMPE is then revealed by ferromagnetic resonance measurements. Resonant fields are shifted under CMPE, whereas their linewidths remain constant. Furthermore, resonant field shifts can be either positive or negative depending on the in-plane angle. The largest shift under CMPE of +5.7~\% is obtained for the 5~nm sample. Our study shows that the CMPE provides an efficient approach for a control of not only the static but also the dynamic magnetic properties in extrinsic multiferroics.
The study of nanophase and nanostructured materials constitutes a new branch of materials research. New magnetic properties emerge in these systems, because their dimensions are below the characteristic length-scales of magnetic interactions. These may be exploited to produce soft magnetic materials [1], permanent magnets [2], and magnetic recording materials [3]. In particular, in Fe-based soft magnetic nanomaterials, the magnetic moments are coupled over distances much larger than the grain diameter. The effective anisotropy, determined by averaging over the randomly-oriented individual particles, is orders of magnitude smaller than the individual grain magnetocrystalline anisotropy [4]. It results that ultra-soft magnetic properties occur. In Nd-Fe-B or Sm-Co nanomaterials, due to the large magnetocrystalline anisotropy of the constitutive grains, the coupling between moments does not extend significantly beyond the grain boundary. Common alignment of the moments in different grains is restricted to the grain surface, leading to the so-called phenomenon of remanence enhancement [5]. In hard/soft nanocomposites, reversal of the soft phase is impeded by exchange coupling with the hard grains. This, combined with the fact that in the soft phase, the grain size is much smaller than the domain wall equilibrium dimensions, leads to the socalled spring-magnet properties [6, 7].
The various types of nanomaterials described above are usually prepared by fast quenching from the melt, using melt-spinning or a similar technique. These techniques allow large quantities of materials to be industrially produced. They do not offer easy control of the alloy composition nor of the alloy nanostructure. Deformation techniques which were originally developed to reduce the macroscopic dimensions of materials can be an alternative route for the preparation of nanomagnetic materials. They present numerous advantages such as low- cost and simple operation of the equipment as well as easy handling of the materials [8]. At Laboratoire Louis Néel, these techniques have been developed to prepare nanomaterials by cyclic co-deformation of metallic elements in the shape of wires or foils. Arrays of Fe nanowires in a Cu matrix were originally prepared by extrusion [9]. In the second stage, the use of sacrificial aluminum billets allowed materials to be extruded in the shape of platelets without progressive dilution within the matrix. However, attempts to reduce the size of the constitutive elements below typically 0.1 μm were unsuccessful. In his thesis work, A. Giguère then combined extrusion and rolling to prepare Fe/Cu, Fe/Ag, and FeNi/Ag multilayers. He obtained significant GMR signals and was able to directly measure the GMR in the CPP configuration [10].
In these previous studies, the metallic elements involved were immiscible. As the deformation proceeded, the material became progressively harder. Stress-relief heat treatments had to be applied at intermediate stages. The annealing temperatures were low enough so that the internal structure (arrays of wires, multilayer) was not destroyed. The final nanostructure of the materials obtained was intermediate between those of MBE-grown or sputtered multilayers and those of melt-spun materials.
The aim of this thesis was to explore the possibility to prepare magnetic nanomaterials by deforming sub-millimetre thick foils of miscible metals down to the nanometre scale, without applying any heat treatment, and then to produce a given intermetallic phase by applying a final heat treatment of diffusion/reaction between the constitutive elements. We choose the Fe/Pt system, with the main objective of obtaining the hard L10 FePt equiatomic phase. Indeed, it is well known that high performance permanent magnets require both high remanent magnetisation and high coercive field and that both these properties are strongly dependent on the detailed nanostructure of the concerned material. We decided as well to explore the possibility of deforming systems associating rare-earth and transition metal elements and we focussed on the Sm/Fe system on which preliminary work had been realized by A. Giguère in the framework of his thesis work.
This manuscript consists of five chapters. Chapter 1 outlines some general properties of nanostructured materials. It describes deformation mechanisms and various techniques to produce mechanical deformation. Details of the extrusion and sheath-rolling techniques are in particular presented. The detailed preparation procedure of a series of Fe/Pt nanostructured systems is described. These are: FePt, FePt/Ag (Ag was introduced with the aim of improving coercivity), Fe-rich FePt (with the aim of producing exchange-coupled hard/soft FePt/Fe3Pt), and Pt-rich FePt (with the aim of producing exchange-bias FePt/FePt3). The structural properties and the magnetic properties of these various systems are discussed in chapter 2. Chapter 3 is not directly associated with the experimental results presented in this work. It discusses the influence on the intrinsic magnetic properties of exchange-coupling across interfaces in nanostructured heterogeneous systems. Magnetisation reversal in hard FePt and FePt/Fe3Pt is discussed in chapter 4. In this chapter, we consider the effects of dipolar interactions on the magnetic properties of a heterogeneous system and we discuss the results in the framework of a dipolar-spring concept. In chapter 5, the preparation of magnetostrictive SmFe2 rods by co-extrusion of Sm and Fe down to the micrometer scale followed by low- temperature annealing (550°C) is presented.
L’étude des matériaux nanophasés ou nanostructurés constitue une nouvelle branche de la Science des Matériaux. De nouvelles propriétés émergent dans ces systèmes, du fait que leurs dimensions sont inférieures aux portées caractéristiques des interactions magnétiques. Ces propriétés peuvent être exploitées pour produire des matériaux magnétiques doux [1], des aimants permanents [2] ou des matériaux pour l’enregistrement magnétique [3]. En particulier, dans les matériaux magnétiques doux à base de fer, les moments magnétiques sont couplés sur des distances bien supérieures au diamètre des grains constitutifs. L’anisotropie effective, qui résulte d’une moyenne sur l’ensemble de ces grains orientés de façon aléatoire, est de plusieurs ordres de grandeur inférieure à l’anisotropie magnétocristalline de chaque grain [4]. Des propriétés magnétiques ultra-douces en résultent. Dans les nanomatériaux de type Nd-Fe-B ou Sm-Co, en raison de la très forte anisotropie magnétocristalline des grains constitutifs, l’alignement commun des moments entre grains est restreint aux atomes situés au voisinage de la surface des grains, conduisant au phénomène dit de renforcement de rémanence [5]. Dans les nanocomposites doux/durs, le renversement de la phase douce est empêché par le couplage d’échange avec les grains durs. Le fait que la taille des grains doux soit bien inférieure à la dimension d’équilibre des parois de domaines s’ajoute à ceci et entraîne des comportements dits de « spring-magnet » [6, 7].
Les types variés de nanomatériaux décrits ci-dessus sont préparés en général par trempe rapide sur roue à partir du liquide, ou par une technique similaire. De telles techniques permettent de produire de grandes quantités de matériaux à l’échelle industrielle. Elles n’offrent pas un contrôle aisé de la composition des alliages ni de leur nanostructure. Les techniques de déformation mécanique qui ont été développées à l’origine pour réduire les dimensions macroscopiques de matériaux, peuvent constituer une voie alternative d’élaboration de nanomatériaux. Elles présentent plusieurs avantages tels que le faible coût des équipements, leur simplicité d’opération et la manipulation aisée des matériaux [8]. Au laboratoire Louis Néel, ces techniques ont été utilisées pour préparer des nanomatériaux par co-déformation d’éléments métalliques sous forme de fils ou plaques. Des réseaux de nanofils de fer dans une matrice de cuivre ont été tout d’abord préparés par extrusion [9]. Dans une seconde étape, l’utilisation de billettes sacrificielles en aluminium, a permis d’extruder des nanomatériaux sous forme de plaquettes, sans dilution progressive au sein de la matrice. Cependant, les efforts pour réduire la taille des éléments constitutifs en dessous de 0.1 μm environ ont été infructueux. Dans son travail de thèse, A. Giguère a alors combiné extrusion et laminage pour préparer des multicouches de Fe/Cu, Fe/Ag and FeNi/Ag. Il a obtenu des magnétorésistances significatives et a réussi à les mesurer en configuration CPP (Current Perpendicular to Plane) [10].
Dans ces études, les éléments métalliques en jeu étaient immiscibles. A chaque étape de déformation, les matériaux deviennent plus durs mécaniquement. Des traitements thermiques de revenu sont requis aux étapes intermédiaires. Les températures de revenu sont suffisamment basses afin que la structure interne (en réseau de fils ou multicouches) ne soit pas détruite. La nanostructure finale des matériaux est intermédiaire entre celles de multicouches élaborés par EJM (épitaxie par jet moléculaire) ou par pulvérisation cathodique et celles de matériaux élaborés par trempe rapide.
L’objectif de cette thèse était d’explorer la possibilité de préparer des nanomatériaux magnétiques par déformation de feuilles de métaux miscibles, d’épaisseurs initiales inférieures au millimètre, sans aucun traitement thermique jusqu’à l’échelle nanométrique, et de n’appliquer qu’à ce stade le traitement de diffusion-réaction entre les éléments constitutifs, requis pour la formation des phases recherchées. Nous avons choisi le système Fe/Pt, avec pour premier objectif l’obtention de la phase équiatomique dure FePt L10. Il est bien connu que les aimants permanents de haute performance doivent associer une haute aimantation rémanente et une forte coercitivité et que de telles propriétés peuvent dépendre de façon critique de la nanostructure du matériau concerné. Nous avons décidé aussi d’explorer la possibilité de déformer des matériaux associant des éléments de terres rares et de transition et nous nous sommes plus spécialement intéressés au système Sm/Fe auquel A. Giguère avait consacré des travaux préliminaires dans le cadre de sa thèse.
Ce manuscrit est constitué de 5 chapitre. Le chapitre 1 illustre quelques propriétés générales des matériaux nanostructurés. La déformation mécanique est décrite ainsi que des techniques variées de déformation mécanique, plus particulièrement l’extrusion et le laminage sous gaine. Le procédé que nous avons développé pour la préparation de séries de systèmes Fe/Pt nanostructurés est décrit de façon détaillée. Ces systèmes sont FePt, FePt/Ag (l’introduction d’Ag avait pour but d’augmenter la coercitivité), Fe/Pt riche en fer (le but ici était de produire des matériaux nanocomposites durs/doux FePt/Fe3Pt) et FePt riche en Pt (pour obtenir un mécanisme de type décalage d’échange (exchange-bias) entre FePt et FePt3). Les propriétés structurales et les propriétés magnétiques de ces systèmes variés sont discutées au chapitre 2. Le chapitre 3 n’est pas directement lié aux résultats présentés dans ce travail. Je discute l’influence d’un couplage d’échange à travers l’interface sur les propriétés magnétiques intrinsèques de systèmes nanostructurés hétérogènes. Au chapitre 4, je discute le renversement d’aimantation dans FePt et FePt/Fe3Pt. Je considère les effets des interactions dipolaires sur les propriétés magnétiques de systèmes hétérogènes. Au chapitre 5, je décris la préparation de barreaux magnétostrictifs SmFe2 par co-extrusion de Sm et Fe jusqu’à l’échelle miconique, suivie d’un traitement de recuit à basse température (550°C).
Searching for materials that possess a combination of excellent magnetic softness and vanishing magnetostriction, the ferromagnetic high‐entropy alloy (HEA) system AlCoFeNiCux (x = 0.6–3.0) is investigated. Superior magnetostriction and magnetic softness parameters are obtained for the composition AlCoFeNiCu2.0, which shows zero magnetostriction, λs = 0, low coercivity Hc ≈ 650 A m−1 and substantial saturation magnetic polarization of Js ≈ 0.55 T. The parameters of other AlCoFeNiCux compositions in the range x = 2.0–3.0 are only slightly different, so that the entire set of the AlCoFeNiCux HEAs in that Cu content range can be classified as magnetically soft and vanishing‐magnetostriction alloys. The alloys develop a multiphase (up to three phases) composite microstructure that is further nanostructured on the 10 nm scale. Magnetic softness of the alloys originates from the exchange‐averaging of magnetic anisotropy, while vanishing magnetostriction coefficient of the AlCoFeNiCu2.0 alloy results from its three‐phase microstructure, where the magnetostrictions of different signs exactly compensate each other at particular volume fractions. The AlCoFeNiCux (x = 2.0–3.0) HEAs are expected to find applications as supersilent (inaudible to a human ear) materials for transformers, magnetocaloric coolers, and other “humming” electromagnetic machinery. The ferromagnetic high‐entropy alloy system AlCoFeNiCux (x = 0.6–3.0) is investigated to find materials with a combination of excellent magnetic softness and vanishing magnetostriction. Zero magnetostriction and superior magnetic softness are obtained for the compositions x = 2.0–3.0. The materials may find application as supersilent (inaudible to a human ear) materials for transformers and other “humming” electromagnetic machinery.
In this chapter, the physical principles underlying the phenomenologies arising from the magnetoelastic coupling occurring in materials exhibiting ferromagnetic order are first reviewed. From those principles, several generic designs of magnetoelastic sensors are discussed and, with special detail, that corresponding to resonant sensors. Finally, exemplary biomedical applications of magnetoelastic sensors to the measurement of the mechanical stress in bone fractures healing plates, sutures, and laryngeal muscles, the monitoring of the local curvature of epithelial tissues, the control of cell growth, and the measurement of blood coagulation kinetic parameters are reviewed. We conclude with a brief vision on the future perspectives of the magnetoelastic sensing technology and its biomedical applications. Although unexplored to date in the context of traumatically injured neural tissues, we hope these biomedical approaches, secondarily benefitting patients with traumatic brain and spinal cord injuries, could inspire advances in the field toward their implementation for neural scenarios.
The magnetostriction phenomenon, which exists in almost all magnetically ordered materials, is proved to have wide application potential in precision machinery, microdisplacement control, robotics, and other high‐tech fields. Understanding the microscopic mechanism behind the magnetostrictive properties of magnetically ordered compounds plays an essential role in realizing technological applications and helps the fundamental understanding of magnetism and superconductivity. In paramagnets, however, the magnetostriction is usually significantly smaller because of the magnetic disorder. Here, the observation of a remarkably strong magnetostrictive response of the insulator paramagnet KEr(MoO4)2 is reported on. Using low‐temperature magnetization and dilatometry measurements, in combination with ab initio calculations, employing a quasi‐atomic treatment of many‐body effects, it is demonstrated that the magnetostriction anomaly in KEr(MoO4)2 is driven by a single‐ion effect. This analysis reveals a strong coupling between the Er3+ ions and the crystal lattice due to the peculiar behavior of the magnetic quadrupolar moments of Er3+ ions in the applied field, shedding light on the microscopic mechanism behind the massive magnetostrictive response. The paramagnetic single‐crystal insulator KEr(MoO4)2 exhibits a remarkable change of its size in a magnetic field. This experimental feature exceeds the analogous effect in other paramagnets and rare‐earth alloys by an order of magnitude. The provided theoretical approach explains the mechanism behind this effect. The tunability of the crystal size provides excellent perspectives for applications in magnetic and cryogenic technologies.
Systematic experimental results on the Matteucci effect in torsioned magnetostrictive FeSiB microwire are introduced, observed during the propagation of a single domain wall (DW) under the action of axial driving magnetic field, Hdr. These data are discussed, reviewing current bibliography models and proposing new perspectives. The unidirectional DW velocity is quantified by voltage induced in tiny pickup coils along the microwire. The Matteucci electromotive force (emf) induced between the microwire's ends is associated with depinning and annihilation of the DW, introducing a new method to measure DW velocity. The emf amplitude is proportional to the DW velocity and the time derivative of the azimuthal magnetization, tailored by applied torsion. The data confirm the existence of net values of azimuthal magnetization and spontaneous torsion induced during fabrication. The clockwise/counterclockwise applied torsion dependence of Matteucci emf and DW velocity are experimentally determined for parallel and antiparallel Hdr. Asymmetric behaviors are observed for both, the sense of applied torsion and the direction of Hdr. The experimental data are discussed in terms of the magnetoelastic anisotropy introduced by torsion. Through analysis of the DW dynamics, such asymmetric behaviors are interpreted as a magnetochiral effect derived from the change of chirality of the propagating wall. The Matteucci effect, ME, in twisted magnetostrictive FeSiB microwire is correlated with the propagation of a single domain wall under an axial driving magnetic field. The asymmetry of both, ME and wall velocity, on the sense of applied torsion and field direction is interpreted in terms of the torsion magnetoelastic anisotropy and the magnetochiral effect of the propagating wall chilarity.
We describe an extension of the micromagnetic finite difference
simulation software MuMax3 to solve elasto-magneto-dynamical
problems. The new module allows for numerical simulations of
magnetization and displacement dynamics in magnetostrictive
materials and structures, including both direct and inverse
magnetostriction. The theoretical background is introduced, and the
implementation of the extension is discussed. The magnetoelastic
extension of MuMax3 is freely available under the GNU General Public
License v3.
In this paper, a magnetostrictive-based optical fiber micro-cantilever resonant magnetic field sensor is proposed. The magnetic field sensor is based on the optical fiber end face design of the optical fiber micro-cantilever beam. The surface of the optical fiber micro-cantilever beam is plated with a magnetostrictive film, and the two form a double layer micro-cantilever beam structure. The magnetostrictive film generates a magnetostrictive effect under a magnetic field, which causes the double-layer cantilever structure to deflect and change its resonant frequency. The magnetic field can be determined by detecting the change in resonant frequency. Then use ANSYS simulation software to simulate the resonance frequency of the double-layer micro-cantilever structure under the magnetic field, and obtain the relationship between the magnetic field and the resonance frequency, in order to optimize the size of the double-layer cantilever structure, and then obtain the best sensitivity of the magnetic field sensor. The simulation results show that: when the double-layer micro-cantilever structure is 90 μm long, the thickness of the fiber-optic micro-cantilever is 2 μm, and the thickness of the magnetostrictive film is 3⁄5 of the thickness of the fiber-micro-cantilever, the magnetic field sensor can reach the maximum sensitivity of 40,760 Hz/Gs.
The spread of the severe acute respiratory syndrome coronavirus has changed the lives of people around the world with a huge impact on economies and societies. The development of wearable sensors that can continuously monitor the environment for viruses may become an important research area. Here, the state of the art of research on biosensor materials for virus detection is reviewed. A general description of the principles for virus detection is included, along with a critique of the experimental work dedicated to various virus sensors, and a summary of their detection limitations. The piezoelectric sensors used for the detection of human papilloma, vaccinia, dengue, Ebola, influenza A, human immunodeficiency, and hepatitis B viruses are examined in the first section; then the second part deals with magnetostrictive sensors for the detection of bacterial spores, proteins, and classical swine fever. In addition, progress related to early detection of COVID‐19 (coronavirus disease 2019) is discussed in the final section, where remaining challenges in the field are also identified. It is believed that this review will guide material researchers in their future work of developing smart biosensors, which can further improve detection sensitivity in monitoring currently known and future virus threats. Piezoelectric and magnetostrictive biosensor materials are presented and discussed. It is found that these advanced materials show great potential for application in the detection of various viruses. Progress related to COVID‐19 (coronavirus disease 2019) and the way to new and emerging sensors for virus detection for home application or wearability are considered.
Przedstawiono wykorzystanie remanencji w badaniach nieniszczących i różne metody zapisu informacji w ferromagnetyku. Szczególną uwagę położono na pomiar rozkładu pola magnetycznego w pobliżu badanego obiektu oraz diagnozowanie lin.
Przedstawiono problemy eksploatacyjne lin kompaktowanych w górnictwie oraz 3 metody magnetyczne badań nieniszczących. Szczególną uwagę zwrócono na metody MRT i MPM oraz prace badawcze mające na celu poprawę wiarygodności diagnozowania lin kompaktowanych.
The possibility of application of the eddy current tomography setup to measure the small permeability variations caused by magnetoelastic effect was presented. A ferromagnetic steel sample was prepared for applying wall stresses and measured for 30 MPa stresses. The Finite Element Method (FEM) was utilized to conduct numerical forward tomography transformation for samples of known permeability. Developed forward tomography transformation was applied for single variable inverse tomography transformation, utilized for determining magnetic permeability. This confirmed the possibility of the application of eddy current tomography for quantitative measurements of magnetoelastic effect in samples of known geometry.
The work presented in this paper shows that Fiber Bragg Grating (FBG) optical fiber sensors can potentially be used as receivers in a long-range guided wave torsional-mode pipe inspection system. Benefits over the conventional pulse-echo method arise due to reduced total travel distance of the ultrasonic guided wave reflections, since reflections from defects and structural features do not need to propagate a full round trip back to the transmitting collar. This is especially important in pipe configurations with high attenuation, such as coated and buried pipelines. The use of FBGs as receivers instead of conventional piezoelectric or magnetostrictive elements also significantly reduces cabling, since multiple FBG receivers can be placed along a single optical fiber which has a diameter on the order of only around 100 μm. The basic approach and sample results are presented in the paper. Additionally, a brief overview of some topics in ultrasonic guided waves is presented as a background to understand the inspection problem presented here.
As a potential magnetostrictive material, Fe-Al alloys exhibit excellent mechanical properties, low cost, and moderate magnetostriction, but the magnetostriction mechanism is still a mystery. Here, we elucidate the structural origin of magnetostriction in Fe-Al alloys and further improve the magnetostriction five-fold via Tb doping. Nanoinclusions with a size of 3–5 nm were found dispersed in the A2 matrix in Fe82Al18 ribbons. The structure of the nanoinclusions is identified to be tetragonally modified-D03 (L60), which are considered to create the tetragonal distortion of the matrix, leading to the enhanced magnetostriction. Furthermore, a drastic enhancement of the magnetostriction up to 5 times was achieved by trace Tb doping (0.2 at. %). Synchrotron X-ray diffraction directly revealed the increased tetragonal distortion of the matrix caused by these Tb dopants. The results further enrich the heterogeneous magnetostriction and guide the development of magnetostrictive materials.
We present a comprehensive study of a magnetic sensor system that benefits from a new technique to substantially increase the magnetoelastic coupling of surface acoustic waves (SAW). The device uses shear horizontal acoustic surface waves that are guided by a fused silica layer with an amorphous magnetostrictive FeCoSiB thin film on top. The velocity of these so-called Love waves follows the magnetoelastically-induced changes of the shear modulus according to the magnetic field present. The SAW sensor is operated in a delay line configuration at approximately 150 MHz and translates the magnetic field to a time delay and a related phase shift. The fundamentals of this sensor concept are motivated by magnetic and mechanical simulations. They are experimentally verified using customized low-noise readout electronics. With an extremely low magnetic noise level of ≈100 pT/[Formula: see text], a bandwidth of 50 kHz and a dynamic range of 120 dB, this magnetic field sensor system shows outstanding characteristics. A range of additional measures to further increase the sensitivity are investigated with simulations.
The consequences of coupling magnetic and elastic degrees of freedom, where spins and deformations are carried by point-like objects subject to local interactions, are studied, theoretically and by detailed numerical simulations. From the constrained Lagrangians we derive consistent equations of motion for the coupled dynamical variables. In order to probe the dynamics of such a system, we consider external perturbations, such as spin transfer torques for the magnetic part, and homogeneous stresses for the elastic part, associated to their corresponding damping. This approach is applied to the study of ultrafast switching processes in anti-ferromagnetic systems, which have recently attracted attention as candidates for anti-ferromagnetic spintronic devices. Our strategy is then checked in simple, but instructive, situations. We carried out numerical experiments to study, in particular, how the magnetostrictive coupling and external stresses affect the nature of the switching processes in a prototype anti-ferromagnetic material.
In the coming era of the internet of things (IoT), wireless sensor networks that monitor, detect, and gather data will play a crucial role in advancements in public safety, human healthcare, industrial automation, and energy management. Batteries are currently the power source of choice for operating wireless network devices due to their ease of installation; however, they require periodic replacement due to capacity limitations. Within the scope of the IoT, battery maintenance of the trillion sensor nodes that may be implemented will be practically infeasible from environmental, resource, and labor cost perspectives. In considering individual self-powered sensor nodes, the idea of harvesting energy from ambient vibrations, heat, and electromagnetic waves has recently triggered noticeable research interest in the academic community. This paper gives an overview of energy harvesting materials and systems. Three main categories are presented: piezoelectric ceramics/polymers, magnetostrictive alloys, and magnetoelectric (ME) multiferroic composites. State-of-the-art harvesting materials and structures are presented with a focus on characterization, fabrication, modeling and simulation, and durability and reliability. Some perspectives and challenges for the future development of energy harvesting materials are also highlighted.
The present paper deals with the characterization of the magnetostriction of the Fe-27%Co alloy. When this alloy is annealed in the ferritic domain (between 700°C and 940°C) and submitted to a slow cooling, it exhibits a low and isotropic magnetostriction over a wide induction range (±1.5T). One reason that can explain this phenomenon is a high temperature selection of magnetic bi-domains preferentially oriented in the rolling plane. As soon as this material is annealed in the austenitic domain or quenched from the ferritic domain, the low and isotropic magnetostriction disappears giving way to a classical quadratic magnetostrictive behavior.
Development of miniaturized magnetostriction-associated devices requires low-field-triggered large magnetostriction. In this study, we acquired a large magnetostriction (800 ppm) triggered by a low saturation field (0.8 kOe) in iron-palladium (Fe-Pd) alloys. Magnetostriction enhancement jumping from 340 to 800 ppm was obtained with a slight increase in Pd concentration from 31.3 to 32.3 at. %. Further analysis showed that such a slight increase led to suppression of the long-range ordered martensitic phase and resulted in a frozen short-range ordered strain glass state. This strain glass state possessed a two-phase nanostructure with nanosized frozen strain domains embedded in the austenite matrix, which was responsible for the unique magnetostriction behavior. Our study provides a way to design novel magnetostrictive materials with low-field-triggered large magnetostriction.
A capacitor bridge dilatometer is described ; its characteristic ΔC = /(Δl) is perfectly linear for any displacement of the moving electrode less than 100 µm. This device allows us to measure the longitudinal magnetostriction of one centimeter samples, in the range from 10-8 to 5 x 10 -3, in a field strength up to 9 kOe and at any temperature below 900 °K. On décrit un dilatomètre à pont de capacités, dont la caractéristique ΔC = f(Δl) est parfaitement linéaire pour tout déplacement de l'électrode mobile inférieur à 100 microns, Ce dispositif permet de mesurer la magnétostriction longitudinale d'échantillons de 1 cm de long dans la gamme 10-8 à 5 x 10-3, dans un champ de 9 kOe, et à toutes températures jusqu'à 900 °K.