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PR amplitude in picometer per volt of applied ac sample bias as a function of function of ac bias frequency for contact resonance-PFM with MESP cantilever and paddle resonance of a PAC.
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A cantilever type has been developed for dynamic force microscopy by the addition of a harmonic oscillator in the form of a paddle to atomic force microscopy cantilevers. These cantilevers provide resonant amplification of periodic interactions between the probe and the substrate when the laser is aligned on the paddle. The cantilevers were explore...
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... the signal to noise ratio during scanning, section analysis was performed on Figs. 3b and 3e, respectively, as shown in Fig. 4. The dotted line denotes the PAC PR amplitude, whereas the com- plete line denotes the MESP PR amplitude. The PAC shows at least three times as much signal as MESP cantilever, vali- dating the frequency response data from Fig. 2. However, the signal as well as noise in the measurements gets amplified. This effect and the influence of probe area on the measure- ments are currently under investigation. Thus the out-of- plane PR vector was completely measured and quantified using PACs with signals as good as or better than commonly used MESP cantilevers in ...Similar publications
We report the first experimental observation of discrete quadratic interface solitons existing at the edge of a PPLN waveguide array. Both in-phase and staggered discrete surface solitons were observed.
Continuous wave ultraviolet laser irradiation at λ = 244 nm on the +z face of undoped and MgO doped congruent lithium niobate single crystals has been observed to inhibit ferroelectric domain inversion. The inhibition occurs directly beneath the illuminated regions, in a depth greater than 100 nm during subsequent electric field poling of the cryst...
Citations
... One solution to enhance the overall motion while maintaining a compact geometric envelope is to serially connect several stages in a folded manner; this approach has been applied to the microcantilever-in-microcantilever designsee Ref. [17] and also Refs. [18,19]-which is sketched in Fig. 2. ...
... Figure 16 plots the ratios w n /w 1 and r n /r 1 in terms of the maximum number of circular segments n. These two ratios are related as w n w 1 = r n r 1 3 (19) in terms of the maximum number of circular segments n. This plot used the following numerical parameters: C = 1 m/N, r 1 = 0.008 m, t = 0.0005 m, g = 0.002 m, E = 2 × 10 11 N/m 2 , and ν = 0.3. ...
... The radius ratio increases quasilinearly with n, while the width ratio (as per Eq. (19)) increases nonlinearly with the cube of the radius ratio. ...
This research proposes the self-similarity design concept of flexible mechanisms by studying the out-of-plane, piston motion of a compliant device. Self-similar compliant mechanisms can be formed by connecting flexible units of scaled-down, identical geometry in series and/or parallel. We study a folded-architecture, compact mechanism class formed of multiple flexible, circular, and concentric segments that are serially connected. The device is capable of producing large displacements by summing the small deformations of its units. A simple analytical model is derived, which predicts the mechanism piston compliance/stiffness in terms of configuration, geometry, and material parameters. Experimental testing of a prototype and finite element simulation of various designs confirm the validity of the mathematical model. Several particular designs resulting from the generic architecture are further characterized based on the analytical model to highlight the mechanism stiffness performance and the way it scales with its defining parameters and unit stiffness.
... Tapping mode atomic force microscopy (TM-AFM) is widely used in measurement of semiconductor devices and 1 3 Zeyen et al. 2009;Zhang et al. 2017). Hodges proposed a probe that has two slim legs (Hodges et al. 2001). ...
... Kimura et al. introduced an elastic hinge to cantilever probe to increase the "effective slope" of the free end (Kimura et al. 2007). Zeyen et al. proposed a probe by adding a paddle (Zeyen et al. 2009). In these methods, however, designers usually need a lot of trials and errors before arriving at a proper position to add the special structural feature or its proper shape and sizes. ...
To enhance the measurement performance of tapping-mode atomic force microscopy (TM-AFM), it is highly desirable that the TM-AFM probe has high resonant frequency and large effective slope at its free end. However, the two design objectives may lead to conflict requirements on the geometry of probe. Conventional design approaches that involve a lot of trials and errors are not so effective to solve such a complex design problem. Therefore, in order to address this difficulty, a structural optimization problem is formulated. The objective of optimization is to ensure the mode shape of probe match a user-specified target shape and the corresponding resonant frequency is maximized. Similarity between the actual mode shape and the target is characterized by modal assurance criterion. Users can freely select which vibration mode is to be optimized. A three-layer geometry model is used to represent cantilever probes. The middle layer is not subject to optimization. The top and bottom layers have the same width profile, and it is iteratively changed during the optimization. The optimization problem is solved through a gradient based method. Examples of design optimization show that the proposed method is effective.
... Because of these limitations of current technology there is an interest in alternate methods, beyond the use of small microcantilevers, to boost the OLS of conventional microcantilevers. Some authors have proposed to enhance the OLS by modifying the design of the conventional microcantilevers [22][23][24][25]. Specifically, harmonic cantilevers [22] or tuned embedded second cantilever [23] have been proposed for boosting the SNR of higher harmonic signals in dynamic AFM. ...
... Paddles embedded in cantilevers have also been used in different contexts to amplify SNR for cantilever tips in continuous contact with the sample. For example, the addition of a paddle shaped harmonic oscillator to triangular AFM cantilevers [24] has been proposed for piezoresponse force microscopy [26]. These cantilevers are designed such that their contact resonance frequency is higher than the paddle's resonance frequency. ...
... The higher the Q-factor of a mode in the cantilever the longer is the ringing and the better is the SNR of the absorption signal. While geometrically similar to our proposed design, the goals and applications of our probe design are quite different from those of [24,25] and require different considerations of the dynamic properties of the probe. ...
A method is presented to enhance the optical lever sensitivity in dynamic atomic force microscopy (AFM) by nearly an order of magnitude over a wide frequency bandwidth. This is achieved by fabricating or releasing a paddle with a soft hinge close to the free end of the AFM microcantilever such that the paddle resonance frequency is well below the fundamental resonance frequency of the microcantilever. We show a significant increase in signal to noise ratio when cantilever motion is observed at the paddle for AFM systems that are not limited by thermal noise. Also, any effects due to the excitation of the second eigenmode were decoupled by locating the paddle at the node of the second eigenmode. We use these probes for higher harmonic imaging in amplitude modulated AFM (AM-AFM) on a standard polymer blend made of polystyrene and low density polyethylene. We demonstrate significantly improved contrast in higher harmonic images when observing cantilever motion at the paddle. Thus this microcantilever design can improve significantly conventional cantilever performance for dynamic AFM and is compatible with low-cost, high yield microfabrication processes.
... Recently, a number of sensor configurations using membrane-type detectors have been suggested to circumvent this problem [67][68][69]. Similarly, cantilever sensors for optical detection are constantly being developed, with notable examples including small single-crystal Si cantilevers [70], paddle beam preamplifying cantilevers [71], paddle beam cantilevers to tailor the harmonic resonance responses [72], microfabricated tribolevers for friction measurements [68], small cantilevers [73] for force spectroscopy and high-speed imaging, and dual-frequency (two cantilevers in series) cantilevers [74]. Although the optical beam detector [75] has not been displaced as the dominant form of cantilever detection, there have been many attempts at producing cantilevers that are self-sensing -that is, that have integrated detection schemes, most notably piezolevers, which do not require laser beam alignment. ...
... The cantilever geometry can be selected to vibrate in a manner that is sensitive to the substrate thermomechanical deflections [19][20][21]. We started with commercially available rectangular microcantilevers of length 350 µm, width 35 µm, . ...
Infrared (IR) spectroscopy is one of the most widely used techniques for identifying and characterizing materials, but is diffraction limited to a spatial resolution of no smaller than several micrometers. This paper reports IR spectroscopy with 100 nm spatial resolution, using a tunable laser whose absorption in an organic layer is measured via atomic force microscopy. Wavelength-dependent absorption in the sample results in local thermomechanical deformation, which is sensed using the sharp tip of a resonant atomic force microscope cantilever. We introduce a cantilever and system design capable of 100 nm spatial resolution and a 6 x sensitivity improvement over previous approaches.
Atomic Force Microscopy (AFM) has been widely utilized to gain insight into various material and structural functionalities on the nanometer scale, leading to numerous discoveries and technologies. Despite the phenomenal success in applying AFM to the simultaneous characterization of topological and functional properties of materials, it has continuously suffered from the crosstalk between the observables, causing undesirable artifacts and complicated interpretations. Here, we introduce a two-field AFM probe, namely an inner-paddled cantilever integrating two discrete pathways such that they respond independently to the variations in surface topography and material functionality. Hence, the proposed design allows reliable and potentially quantitative determination of functional properties. In this paper, the efficacy of the proposed design has been demonstrated via Piezoresponse Force Microscopy (PFM) of periodically poled lithium niobate (PPLN) and collagen, although it can also be applied to other AFM methods such as AFM-based Infrared (AFM-IR) spectroscopy and Electrochemical Strain Microscopy (ESM). Keywords: atomic force microscopy, contact-mode functional AFM, piezoresponse force microscopy, contact resonance, inner-paddled microcantilever.
Higher harmonics signal in tapping mode atomic force microscope (AFM) topography imaging process is verified to be an evidence for material mapping in sample surface. Due to low amplitude and rapid decay of higher harmonics, structure design focused on cantilever probe is proposed to optimize the frequency response performance of probe. Here, we utilize concentrated masses to tune the ratio between eigenfrequencies for tip attached probe. Euler-Bernoulli beam theory is the fundamental for analysis. We figure out that adding masses can realize the tailoring of eigenfrequency ratios, and two concentrated masses will produce more frequency combination candidates than one concentrated mass. Probe with integer ratios between eigenfrequencies generates high sensitive responses at corresponding higher harmonics.
We describe an atomic force microscope cantilever design for which the second flexural mode frequency can be tailored relative to the first mode frequency, for operation in contact with a substrate. A freely resonating paddle internal to the cantilever reduces the stiffness of the second flexural mode relative to the first while nearly maintaining the mass of the original cantilever. Finite element analysis is used to predict the performance of various cantilever designs and several cantilevers are fabricated and tested. This strategy allows the ratio of the first two resonant modes f2/f1 to be controlled over the range 1.6–4.5. The ability to vary f2/f1 could improve a variety of dynamic contact-mode measurements.
Nonvolatile bias-controlled polarization states in ferroelectric materials offer unique opportunities for information technology
and data storage applications. The ability to probe ferroelectric properties at the nanoscale by piezoresponse force microscopy
(PFM) has enabled fundamental studies of polarization dynamics and the role of defects and disorder on domain nucleation and
wall motion and has led to advances in the design and implementation of such applications. This has resulted in the development
of fast spectroscopic modes to collect polarization switching data from every point in an image. The emergence of fast, configurable
data processing electronics has prompted the development of dynamic and nonsinusoidal data acquisition methods for PFM. Further,
the recent synergy of spectroscopic and dynamic modes has necessitated the development of multivariate data analysis and processing
in PFM. These recent advances in the applications of PFM for imaging and spectroscopy of the ferroelectric switching processes
will be discussed.
