Ferroelastic Domains and Anisotropy in Lead Free Piezoelectrics

2011 ◽  
Vol 702-703 ◽  
pp. 995-998
Author(s):  
Bin Zhi Li ◽  
Chris Fancher ◽  
John E. Blendell ◽  
R. Edwin Garcia ◽  
Keith J. Bowman

Our research investigates the correlations between domain texture and microstructural features, including crystallographic texture in bulk and thin film polycrystalline materials to understand the development of piezoelectric and other anisotropic properties in a number of rapidly evolving lead free piezoelectric materials. We investigate approaches to understanding polarization distributions by starting from polarization measurements. In addition, 2D and 3D microstructural simulations are carried out in all types of ferroelectrics to rationalize and then engineer their equilibrium and kinetic response. This paper discusses recent findings associated with bulk piezoelectricity, phase stability, and ferroelastic and ferroelectric domain motion for materials such as Ba(Ti0.8Zr0.2)O3-x(Ba0.7Ca0.3)TiO3 (BZT-BCT) and Bi0.5Na0.5TiO3 (BNT). Conventional and synchrotron-based x-ray diffraction, electron and optical microscopy and piezoelectric characterization techniques are employed to assess texture, both as a function of poling and temperature. The coupling between microstructure and the inherent directional biases fundamental to piezoelectric and ferroelectric performance enable consideration of orientation and anisotropy in systems with unique constraints.

1993 ◽  
Vol 29 (1) ◽  
pp. 300-306 ◽  
Author(s):  
J.A. Bain ◽  
B.M. Clemens ◽  
S.M. Brennan ◽  
H. Kataoka

2021 ◽  
Author(s):  
Anggel Lagunas ◽  
Maria Guadalupe Navarro-Rojero ◽  
Maria Dolores Salvador ◽  
Jose Manuel Catalá ◽  
Amparo Borrell

Abstract Powders of K0.5Na0.5NbO3 lead-free piezoelectric ceramics were successfully synthesized via conventional and microwave-assisted heating. A single-mode microwave equipment was used to perform the synthesis following the mixed oxide route and then sintering at different temperatures. The synthesized powders obtained and then sintered by microwave and conventional methods were evaluated by thermogravimetry analysis, X-ray diffraction (XRD), and field emission scanning electron microscopy. Microwave synthesis processing for 10 minutes at 650 ºC using a heating rate of 30 ºC/min promotes the formation of 2 K0.5Na0.5NbO3 nanoparticles. Perovskite structure formed during calcination shows the coexistence of tetragonal-orthorhombic geometry according to XRD patterns. The microwave-obtained particles are consistent with the theoretical stoichiometry. Particle size increases as the reaction temperature is increased from 650 ºC to 800 ºC. An intermediate phase (K,Na)2Nb4O11 is formed in the entire range of synthesis temperatures studied. The samples obtained by microwave sintering show a structure similar to the samples sintered by the conventional method. However, the porosity observed in the microstructure of the microwave-sintered piezoelectric materials affects the density of the material, and these defects cause a decrease in the dielectric values.


2003 ◽  
Vol 775 ◽  
Author(s):  
Donghai Wang ◽  
David T. Johnson ◽  
Byron F. McCaughey ◽  
J. Eric Hampsey ◽  
Jibao He ◽  
...  

AbstractPalladium nanowires have been electrodeposited into mesoporous silica thin film templates. Palladium continually grows and fills silica mesopores starting from a bottom conductive substrate, providing a ready and efficient route to fabricate a macroscopic palladium nanowire thin films for potentially use in fuel cells, electrodes, sensors, and other applications. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate it is possible to create different nanowire morphology such as bundles and swirling mesostructure based on the template pore structure.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. K. Eseev ◽  
A. A. Goshev ◽  
K. A. Makarova ◽  
D. N. Makarov

AbstractIt is well known that the scattering of ultrashort pulses (USPs) of an electromagnetic field in the X-ray frequency range can be used in diffraction analysis. When such USPs are scattered by various polyatomic objects, a diffraction pattern appears from which the structure of the object can be determined. Today, there is a technical possibility of creating powerful USP sources and the analysis of the scattering spectra of such pulses is a high-precision instrument for studying the structure of matter. As a rule, such scattering occurs at a frequency close to the carrier frequency of the incident USP. In this work, it is shown that for high-power USPs, where the magnetic component of USPs cannot be neglected, scattering at the second harmonic appears. The scattering of USPs by the second harmonic has a characteristic diffraction pattern which can be used to judge the structure of the scattering object; combining the scattering spectra at the first and second harmonics therefore greatly enhances the diffraction analysis of matter. Scattering spectra at the first and second harmonics are shown for various polyatomic objects: examples considered are 2D and 3D materials such as graphene, carbon nanotubes, and hybrid structures consisting of nanotubes. The theory developed in this work can be applied to various multivolume objects and is quite simple for X-ray structural analysis, because it is based on analytical expressions.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Lars Banko ◽  
Phillip M. Maffettone ◽  
Dennis Naujoks ◽  
Daniel Olds ◽  
Alfred Ludwig

AbstractWe apply variational autoencoders (VAE) to X-ray diffraction (XRD) data analysis on both simulated and experimental thin-film data. We show that crystal structure representations learned by a VAE reveal latent information, such as the structural similarity of textured diffraction patterns. While other artificial intelligence (AI) agents are effective at classifying XRD data into known phases, a similarly conditioned VAE is uniquely effective at knowing what it doesn’t know: it can rapidly identify data outside the distribution it was trained on, such as novel phases and mixtures. These capabilities demonstrate that a VAE is a valuable AI agent for aiding materials discovery and understanding XRD measurements both ‘on-the-fly’ and during post hoc analysis.


1988 ◽  
Vol 119 ◽  
Author(s):  
Hung-Yu Liu ◽  
Peng-Heng Chang ◽  
Jim Bohlman ◽  
Hun-Lian Tsai

AbstractThe interaction of Al and W in the Si/SiO2/W-Ti/Al thin film system is studied quantitatively by glancing angle x-ray diffraction. The formation of Al-W compounds due to annealing is monitored by the variation of the integrated intensity from a few x-ray diffraction peaks of the corresponding compounds. The annealing was conducted at 400°C, 450°C and 500°C from 1 hour to 300 hours. The kinetics of compound formation is determined using x-ray diffraction data and verified by TEM observations. We will also show the correlation of the compound formation to the change of the electrical properties of these films.


1990 ◽  
Vol 7 (7) ◽  
pp. 308-311
Author(s):  
Li Chaorong ◽  
Mai Zhenhong ◽  
Cui Shufan ◽  
Zhou Junming ◽  
Yutian Wang

MRS Advances ◽  
2016 ◽  
Vol 1 (39) ◽  
pp. 2711-2716 ◽  
Author(s):  
V. Vasilyev ◽  
J. Cetnar ◽  
B. Claflin ◽  
G. Grzybowski ◽  
K. Leedy ◽  
...  

ABSTRACTAlN thin film structures have many useful and practical piezoelectric and pyroelectric properties. The potential enhancement of the AlN piezo- and pyroelectric constants allows it to compete with more commonly used materials. For example, combination of AlN with ScN leads to new structural, electronic, and mechanical characteristics, which have been reported to substantially enhance the piezoelectric coefficients in solid-solution AlN-ScN compounds, compared to a pure AlN-phase material.In our work, we demonstrate that an analogous alloying approach results in considerable enhancement of the pyroelectric properties of AlN - ScN composites. Thin films of ScN, AlN and Al1-x ScxN (x = 0 – 1.0) were deposited on silicon (004) substrates using dual reactive sputtering in Ar/N2 atmosphere from Sc and Al targets. The deposited films were studied and compared using x-ray diffraction, XPS, SEM, and pyroelectric characterization. An up to 25% enhancement was observed in the pyroelectric coefficient (Pc = 0.9 µC /m2K) for Sc1-xAlxN thin films structures in comparison to pure AlN thin films (Pc = 0.71 µC/m2K). The obtained results suggest that Al1-x ScxN films could be a promising novel pyroelectric material and might be suitable for use in uncooled IR detectors.


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