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Influence of thermal treatments on the elastic parameters in iron rich metallic glasses
Abstract
The change of magnetoelastic properties after thermal treatments has been investigated for two groups of metallic glasses. (Fe79Co21)75+xSi15−1.4xB10+0.4x (x(at.%)=0, 2, 4, 6, 8, 10) has been studied both in the as-prepared state and after thermal annealing in an applied magnetic field, to achieve a particular domain structure, at temperatures well below the crystallization temperatures. Changes in the ΔE effect, magnetomechanical coupling (k) and internal friction coefficient (Q−1) are reported, reaching values of about 60% of the saturation value ES. Fe64Ni10Nb3Cu1Si13B9 alloys annealed in vacuum for 1h in the temperature range 350–550°C showed maximum values of the ΔE effect and k of 61% and 0.85, respectively, accompanied by a minimum value of Q of around 2 for the sample annealed at 460°C. These variations are related to the progress of nanocrystalization. The properties achieved are among the best reported for magnetomechanical applications.
... The sensitivity was found to be 4. of 700 T. However, the quality factors (Q-factor) of the resonators based on Metglas is inevitably poor due to the low mechanical Qfactor of amorphous material [8,9]. We also note that the Q-factor of the composite resonators are restricted to low values (e.g., 260 for SiO 2 /Pt/AlN/FeCoSiB [5], 250 for AlN/(FeGaB/Al 2 O 3 @ 15 Oe [6]) due to the low mechanical Q-factor of magnetostrictive material. ...
... This induces the field-dependent magnetomechanical damping including macroscopic and microscopic eddy current loss in the magnetostrictive layer. For a MPLC, the effective Q-factor of the vibrator also can be given by [22] 1 Q = n m Q mag + n p Q piezo + 1-n m -n p Q elec (9) where,Q mag is the effective Q-factor of the magnetostrictive layer, Q piezo is the effective Q-factor of the piezoelectric layer,Q elec is the effective Q-factor of the electrode layers, n m is the volume ratio of the magnetostrictive layer in the laminate composite, n p is the volume ratio of the piezoelectric layer in the composite,1 − n m − n p is the volume ratio of the electrode layer in the composite. From (9), the Q-factor of a vibrator or resonator based on a MPLC accordingly depends on the magnetic field due to the field-dependent effect of magneto-mechanical damping. ...
A static/quasi-static magnetic field sensor is developed by using a double ended trip-beam tuning fork (TBTF), a TbxDy1-xFe2-y plate and several piezoelectric Pb(Zr1−xTix)O3 (PZT) plates. The TBTF is boned horizontally across two ceramic supports which are fixed on the ends of the TbxDy1-xFe2-y plate. The magnetostrictive stress induces an axial force in the TBTF, which causes the resonance frequency of the TBTF to increase. The theoretical analysis shows that the magnetostrictive stress increases approximately linearly with the increase of the external DC field, and so does the resonance frequency shift of the TBTF. The magnetostrictive stress can get to 32.65MPa at the field of 1000Oe, and the total frequency shift respectively achieves 2.97% and 16.67% under the assumption of 10% and 60% transmission efficiencies (as the sectional area of the magnetostrictive plate being 6mm×1mm). A Be-bronze TBTF based sensor was fabricated, and the frequency shift of 2.1% was obtained by applying a DC magnetic field in the range of 0–1000Oe. The magneto-mechanical damping in the magnetostrictive plate has no influence on the quality factor of the TBTF which is found to be relatively constant after an initial increase. The results show the great potential to realize a high sensitivity magnetic sensor featuring high quality factor and digital frequency output.
... Nan et al. [11] demonstrated a 215-MHz nano-electromechanical systems (NEMS) resonator based on AlN/(FeGaB/Al 2 O 3 ) multilayer with a detection limit of 300 pT for dc magnetic fields [11]. In general, caused by the high magnetomechanical damping (MMD) [12], [13] in magnetostrictive alloys, the resonant magnetic sensor based on ME laminate is significantly restricted to have low-Q-factor, which is usually lower than 1000 for SiO 2 /Pt/AlN/FeCoSiB MEMS resonator [9], [10] and 735 for AlN/(FeGaB/Al 2 O 3 ) NEMS resonator [11]. Moreover, another regrettable shortcoming is that the Qfactor of the resonators is highly sensitive to the applied dc field, attributed to the field-dependent MMD. ...
A resonant magnetic field sensor is developed by using a piezoelectric quartz crystal double-ended tuning fork (DETF), two FeGa thin plates, and four quartz spacers. The double ends of the DETF are bonded to the ends of the magnetostrictive thin plates through four spacers with adhesive, allowing the magnetostrictive force to be converted into the longitudinal force in the DETF which leads to an increase of the resonant frequency of the DETF. This design brings the advantage of field-independent damping, i.e., the quality factor (Q-factor) of the sensor is found to be independent on the dc field, with an average value of about 3318 in the air due to the low internal loss in quartz. After an initially slow increase before the field reaching ~50 Oe, the resonant frequency of the sensor increases linearly with the increase of the applied dc field before reaching 280 Oe. The total frequency shift, sensitivity of the frequency shift per magnetic field, and field resolution in the linear region are 2.12% (~808.3 Hz), 3.5 Hz/Oe and 8 mOe, respectively. The results demonstrate a possibility and promising to realize a highly sensitive magnetic sensor with high-Q-factor quartz crystal as well as direct digital frequency output.
A type of differential resonant magnetic field sensor is developed by employing the composite elements of FeGa plates, piezoelectric quartz crystal double-ended tuning forks (DETFs) and bias permanent magnets. The model and analysis show that the differential design brings the benefits of doubled sensitivity, increased linearity and low temperature drift. Importantly, a small and compact magnetic circuit containing a pair of permanent magnets and dual FeGa plates ensures the generation of differential actuation, which not only reduces the leakage flux but also improve the field-sensitivity and resolution. The magnetic circuit model based on the “lumped parameters” method is established. As an important aid, the distribution of magnetic flux density along the longitudinal direction of the FeGa alloy is simulated by finite element analysis software. In order to avoid the prediction error caused by parameter errors, simulations in different conditions are carried out for comparative analysis. This method ensures the magnetic circuit provides qualified magnetic field. The experimental results show that the differential resonant magnetic field sensor with frequency readout has the characteristics of high sensitivity of 4.4 Hz/Oe, high resolution of
${< }3.04\times 10^{-4}$
Oe, low temperature drift and excellent linear (non-linearity error of 1.3%FS) and low hysteresis (1.5%FS) over its measurement full scale (FS) of ±100Oe.
The paper is devoted to the detailed analysis of microstructural and magnetic properties of the as-quenched bilayered Co72.5Si12.5B15/Fe77.5Si7.5B15 ribbons prepared by the planar flow casting (PFC) method with single crucible. The interface between both amorphous Co- and Fe-based layers is not uniform and its thickness ranges from 0.5 to 6 mu m over the whole ribbon length. Dependences of mechanical characteristics on the ribbon thickness show increase in Young's modulus from 140 to 170 GPa and decrease in microhardness from 18 to 13 GPa, when measured from the wheel (Co) to air (Fe) side. By fixing the coiled ribbon on the planar sample holder a uniaxial magnetic anisotropy with the out-of-plane and the in-plane easy axis is induced on the air and wheel side, respectively. Bulk magnetic properties confirm that perpendicular anisotropy observed on the air side becomes stronger as getting deeper under the surface and overlaps the in-plane anisotropy from the wheel side. This is in good agreement with Mossbauer measurements. Magnetic characteristics (surface hysteresis loops and domains, bulk hysteresis loops and thermomagnetic curves) of the bilayered samples were further compared with the single-layered CoSiB and FeSiB alloys. (c) 2013 Elsevier B.V. All rights reserved.
The hardness and electronic work function (EWF) of a bulk metallic glass, namely Zr41.2Ti13.8Cu12.5Ni10Be22.5, have been studied experimentally, with an emphasis on the effect of heat treatments. The glass was annealed at different time and temperatures, and its hardness and EWF measured using the Rockwell indentation technique and a scanning Kelvin probe system, respectively. It is found that the EWF decreases with annealing time and temperature, whereas the hardness increases. This study shows a close relationship between hardness and EWF, indicating that the EWF could be a sensitive parameter for characterising and investigating the mechanical behaviour of BMG at the electronic level.
Nanocrystalline structures offer a new opportunity for tailoring soft magnetic materials. The most prominent example are devitrified glassy FeCuNbSiB alloys which reveal a homogeneous ultrafine grain structure of bcc-FeSi with grain sizes of typically 10-15 nm and random texture. Owing to the small grain size the local magneto-crystalline anisotropy is randomly averaged out by exchange interaction so that there is only a small anisotropy net-effect on the magnetization process. Moreover the structural phases present lead to low or vanishing saturation magnetostriction which minimizes magneto-elastic anisotropies. Both the suppressed magnetocrystalline anisotropy and the low magnetostriction provide the basis for the superior soft magnetic properties comparable to those of permalloys or near zero-magnetostrictive Co-base amorphous alloys but at a higher saturation induction. Like in other soft magnetic material the hysteresis loop can be tailored by uniaxial anisotropies induced by magnetic field annealing.
Both as-quenched and annealed (in transverse magnetic field for 1 and 2 h in temperature range from 300 up to 500/spl deg/C) samples of the amorphous alloy of composition F/sub 73.5/Si/sub 16.5/B/sub 6/C/sub 1/Nb/sub 3/ were investigated. The aim of this work was to study the influence of the annealing time and temperature on Young's modulus changes (/spl Delta/E effect) versus magnetic bias field after successive heat treatment up to neighborhood of the nanocrystallization temperature. Elasticity moduli were measured using resonant-antiresonant method. A considerable improvement of the piezomagnetic properties was observed by increasing the annealing temperature up to 480/spl deg/C. Maximum /spl Delta/E effect reached 0.57 after one hour annealing. Annealing at 500/spl deg/C caused sudden drop of the piezomagnetic properties, which can be explained by the decrease of the magnetostriction accompanying the appearance of the nanocrystalline phase.
Internal friction, dynamic Young's modulus and ΔE effect have been
measured in
Fe73.5Cu1Nb3Si13.5B9
ribbons obtained by melt spinning and subsequently submitted to furnace
annealing or Joule heating. The measurements have provided informations
on the different microstructural states and related magnetic behaviour.
The influence of boron content and annealing on the Hall effect and
structure of amorphous
Fe73.5Cu1Nb3Si22.5-
xBx (5<=x<=13) ribbons were studied. The
annealing at 550°C caused a significant change of structure and Hall
coefficient of samples vs. boron content. DSC confirmed the influence of
boron content on crystallization temperature of all samples.
The influence of annealing in vacuum at temperatures of 390°C for 1/2 h and at 400°C for 5 min on the magnetomechanical coupling and ultrasound velocities in Fe79Si12B9 metallic glasses is discussed. Annealing at 390°C improves the magnetochemical coupling (). However, after annealing at 400°C the samples become partially polycrystalline and drops to 0.2. The results are compared with those obtained previously after annealing in air.
A phenomenological description of the first and second order magnetoelastic effects is developed for amorphous ferromagnetic alloys: magnetostriction, DeltaE effect and magnetoelastic contributions to the sound velocities are discussed in detail. A brief description is given of the main experimental methods used to study these effects. A general review of the available data is given for thermal expansion, spontaneous and forced magnetostriction, static elastic properties, acoustic resonance and sound waves propagation under a magnetic field. Laboratoire propre du CNRS, associé à l'Université Scientifique et Médicale de Grenoble.
The aim of this work was to study the influence of annealing on the structure and magnetic properties (bulk and surface coercive field) of an Fe73.5Cu1U3Si13.5B9 alloy. The results confirmed the nanocrystalline character of this alloy in the temperature range 723-813 K.
Magnetoelastic measurements are performed in metallic glasses of composition (Fe0.79Co0.21)75+x. Si15−1.4xB10+0.4x (x = 0, 2, 4, 6, 8, 10) by means of the resonance-antiresonance method. High values of k (magnetoelastic coupling coefficient) and of the ΔY effect are observed in some compositions, reaching 0.7 for k and 50% for ΔY in the as-quenched state. Annealing treatments further improve these values.An amorphen Metallen der Zusammensetzung (Fe0,79Co0,21)75+x Si15−1.4xB10+0.4x (x = 0, 2, 4, 6, 8, 10) werden die magnetoelastischen Größen unter Verwendung der Resonanz-Antiresonanz-methode bestimmt. Hohe Werte von k (der magnetoelastische Koeffizient) sowie vom ΔY-Effekt werden für einige der Legierungen gefunden, mit Werten bis zu 0,7 für k und 50% für ΔY im abgeschreckten Zustand. Noch höhere Werte werden durch Ausglühen erreicht.
The bias magnetic field (H) dependence of the longitudinal sound velocity (v) in Fe77.5Si7.5B15 glass covered amorphous wires is reported. The amorphous wires were tested in the as-cast state and after dc current annealing between 5 and 20 mA for 10–30 min. For the glass covered amorphous wires tested in the as-cast state the bias magnetic field dependence of the sound velocity was insignificant. For current annealed samples a decrease of the sound velocity for the smaller bias magnetic fields was observed. Increasing the annealing temperature, the bias magnetic field corresponding to the vminimum decreased. For about 600 A/m bias magnetic field, the longitudinal sound velocity reaches saturation.
Amorphous metals have magnetomechanical properties superior to those of crystalline magnetostrictive materials, and are therefore being considered for a variety of transducer and sensor applications. A simplified model is presented of magnetomechanical coupling in amorphous metal ribbons, showing the relation between magnetomechanical behavior and fundamental material parameters. Although high values of magnetization and magnetostriction are important, it is primarily the low values of magnetic anisotropy achievable that give amorphous metals their outstanding magnetomechanical coupling. The magnitude and homogeneity of this anisotropy is controllable through choice of alloy composition and annealing conditions.Amorphe Metalle haben bessere magnetomechanische Eigenschaften als kristalline Werkstoffe, und werden deshalb für Anwendungen als Energieumwandler und Kraftübertrager betrachtet. Ein vereinfachtes Modell der magnetomechanischen Kopplung in amorphen metallischen Bändern wird gegeben, das die Beziehung zwischen magnetomechanischem Verhalten und grundlegenden Parametern des Werkstoffes erkärt. Obwohl hohe Werte der Magnetisierung und Magnetostriktion wichtig sind, stammen die hervorragenden magnetomechanischen Kopplungseigenschaften in amorphen Metallen hauptsächlich von den niedrigen Werten der magnetischen Anisotropie. Die Werte und die Homogenität der Anisotropie werden durch die Legierungszusammensetzung und die Anlaßbedingungen kontrolliert.
The metalloid effect on magnetic properties and microstructures of iron‐based alloys with ultrafine grain structures was investigated. For Fe 73.5 Cu 1 Nb 3 (Si x B 1-x ) 22.5 (0.5≤x≤0.8) alloys with 10–15‐nm grain diameters, the permeability increased with Si content. The alloys with x=0.5 and 0.6 subjected to the optimum heat treatment had two different ferromagnetic phases which were composed of an α‐Fe(Si) solid solution with high Curie temperature and an interfacial phase with low Curie temperature. However, in high Si alloys with x=0.7 and 0.8, only a phase with high Curie temperature appeared. This result suggests that in the high Si composition range, a complete transformation from the amorphous phase to the α‐Fe(Si) single phase was achieved. The disappearance of the interfacial phase which would certainly disturb the exchange coupling between the α‐Fe(Si) phase grains would be considered to be one of the factors for the increased permeability.
The magnetic properties of Fe‐Si‐B‐M (M: additives) alloys prepared by annealing amorphous alloys made by the single roller method over their crystallization temperature have been investigated for development of new Fe‐based soft magnetic alloys. Excellent soft magnetic properties were obtained by adding the two elements Cu and Nb to Fe‐Si‐B alloys. It was found that these new alloys, called ‘‘FINEMET,’’ have an ultrafine grain structure composed of bcc Fe solid solution. They are suitable for many kinds of magnetic components such as saturable reactors, choke coils, and transformers, because they have superior soft magnetic properties and a high saturation flux density, and because different types of B‐H hysteresis loops are obtained by magnetic field annealing.
We have measured the perpendicular magnetomechanical coupling, perpendicular susceptibility and shear modulus in polycrystalline Tb .27 Dy .73 Fe 2 by measuring the self-impedance of a cylinder (Wiedemann effect). We find: (1) the maximum value of the perpendicular coupling factor to be greater than .7, considerably higher than the parallel value of .55; (2) the perpendicular susceptibility to be greater than the parallel susceptibility except at zero field where they are equal; (3) a considerably softened shear modulus; (4) an anomalous increase in the skin depth in a narrow range of frequencies above resonance. We present a theory which describes the magnetoelastic behavior and the anomalous skin effect.