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Selected Papers of the Joint International Conference on Applied Physics and Materials Applications & Applied Ferromagnetism and Ferroelectrics (ICAPMA-JMAG-2021)

In this paper, 3D dual impeller stirring tank was used as a model to simulation combine with experiments to explore the acid leaching kinetics of high-calcium and -silicon manganese ores. The effec...

In this paper, the development in the field of ferroelectrics is reviewed by summarizing the topics in the field as presented at the International and European conferences on Ferroelectrics. While ...

In the present paper, we have investigated the electronic structure of some sillenites - Bi12MO20 (M = Ti, Ge, and Si) compounds based on the density functional theory. The mechanical and optical properties of Bi12MO20 have also been computed. The second-order elastic constants have been calculated, and the other related quantities have also been estimated in the present work. The band gap trend in Bi12MO20 can be understood from the nature of their electronic structures. The obtained electronic band structure for all Bi12MO20 compounds is semiconductor in nature. Similar to other oxides, there is a pronounced hybridization of electronic states between M-site cations and anions in Bi12MO20. Based on the obtained electronic structures, we further calculate the frequency-dependent dielectric function and other optical functions.

This paper demonstrates a monolithic surface acoustic wave amplifier fabricated by state-of-the-art heterogenous integration of a III-V InGaAs-based epitaxial material stack and LiNbO3. We compare amplification of Raleigh-SAW and leaky-SAW modes on a on Y-cut, X-propagating delay line amplifier. Due to the superior properties of the materials employed, we observe a net terminal gain of 3dB for an LSAW overtone mode This platform enables further advances in active and non-reciprocal piezoelectric acoustic devices.

The present paper is concerned with the piezoelectric properties and related parameters of the 2–2-type parallel-connected composites wherein rotations of the main crystallographic axes in ferroelectric single crystal components are analyzed. The composite consists of layers of two types that are regularly arranged along the non-polar axis. The Type I layer is a single domain 0.63Pb(Mg1/3Nb2/3)O3–0.37PbTiO3 single crystal (either tetragonal in Composite I or orthorhombic in Composite II). The Type II layer is a Li2B4O7 single crystal/polyethylene medium with 0–3 connectivity. The composite as a whole is characterized by 2–0–2 connectivity. The following parameters of the composite are studied by taking into account the polarization orientation effect in the Type I layer and the microgeometry of the composite in the Type II layer: piezoelectric coefficients (Formula presented.) and (Formula presented.) their hydrostatic analogs (Formula presented.) and (Formula presented.) hydrostatic squared figure of merit (Formula presented.) (Formula presented.) piezoelectric anisotropy factors (Formula presented.) / (Formula presented.) and (Formula presented.) / (Formula presented.) It is shown that large values of the studied piezoelectric coefficients, hydrostatic parameters and anisotropy factors make Composite II more preferable in comparison to Composite I for hydroacoustic, piezoelectric sensor and energy-harvesting applications.

This paper presents a systematic investigation of the electric properties of epitaxial PMN-33PT thin film as a function of temperature and frequency. Complex impedance measurements were performed over the temperature range of 30–500 K and frequency range 20 Hz–1 MHz. Obtained results were corrected for the SRO series resistance. Ferroelectric hysteresis loops and electric field tunability of the real part of dielectric permittivity were measured in the 300 K–450 K temperature range and at a frequency of 1 kHz. The results of electrical field tunability of complex dielectric permittivity were approximated by Landau-Ginsburg-Devonshire theory frame by the Johnson relation. Meanwhile, ferroelectric hysteresis loop measurements of epitaxial PMN-33PT thin film shows a good hysteresis property with a remnant polarization of 2Pr (Formula presented.) 10 µC/cm2 and coercive field of 2Ec (Formula presented.) 12 kV/cm at temperature range from 300 K to 380 K.

This paper presents results on a detailed comparative study of 2–2 relaxor-ferroelectric single crystal / polymer composites. Examples of the hydrostatic piezoelectric performance are discussed for 2–2 composites based on [011]-poled Mn-modified 0.26Pb(In1/2Nb1/2)·O3−0.42Pb(Mg1/3Nb2/3)O3−0.32PbTiO3 single crystals at a molar Mn concentration in the range of 1–5 mol. %. The high piezoelectric activity of these single crystals and rotations of the main crystallographic axes in the single-crystal layers of the composite lead to large values of hydrostatic piezoelectric coefficients , and , squared figure of merit , and electromechanical coupling factor . A rotation mode that leads to a weakening the piezoelectric activity related to the piezoelectric coefficient d32 < 0 is important to achieve composites with a range of large hydrostatic parameters, e.g., ≈ (300–350) pC / N, ∼ 100 mV·m / N, ≈ (21–23) C / m2, ∼ (24–30)·10−12 Pa−1, and ≈ 0.30. In contrast to , higher values of ∼ 10−10 Pa−1 are achieved due to the longitudinal piezoelectric effect. The results obtained in this piezoelectric composite system are interpreted by taking into account the orientation of 71° ferroelectric domains in the single-crystal layers and provide a route to form novel high-performance piezoelectric composites.

Lithium niobate (LiNbO3) is used in applications such as in optoelectronics, surface acoustic wave devices and transducers. In this paper nano-patterning of LiNbO3 wafers at the wafer scale is investigated using a novel low cost and large-area nano-imprinting technique. The formation of nano-scale pillars is presented by nano-imprinting an ordered nickel etch mask by lift-off on a y-cut LiNbO3 wafer. The process lends itself to the development of novel sensors or high temperature nano-scale harvesting structures. Since one potential application for nano-pillars of piezoelectrics is energy harvesting, calculations of relevant figures of merit for LiNbO3 based composites are also presented.

This paper is devoted to the problem of the electromechanical coupling of advanced composites based on relaxor-ferroelectric single crystals with large piezoelectric activity. A novel 0–3–0 PMN–0.33PT single crystal/porous araldite composite is considered as a material with large values of electromechanical coupling factors with a variable anisotropy. The role of physical and microstructural factors in achieving the considerable electromechanical coupling is discussed for 0–3–0 connectivity.

Imaging of domains is a key step in understanding the microstructure and hence the properties of ferroelectric single crystals. In this paper, single crystals of Barium Titanate are observed by reflection topography using unfocussed monochromatic synchrotron X-ray light. The resulting composite images are spatial maps showing regions of distinct microstructure, the proportions of the domain types present, and their orientations. The results are interpreted in the context of models of compatible microstructure in tetragonal crystals; optical microscopy of etched crystals and AFM imaging assist the interpretation. The method shows promise for mapping ferroelectric microstructure.

Magnetic scalar and vector potential approaches in finite element formulation for dynamic response studies of magneto-electro-elastic solids is presented in this paper. The electric field induced by time varying magnetic field is non-conservative and can be described by electric scalar potential and magnetic vector potential. The magnitude of magnetic vector potential is dominant in transverse direction than in longitudinal directions except for FCFC boundary condition. Magnetic scalar potential approach evaluates the components of magnetic flux density on higher side where as electric field intensity is seldom influenced using both the approaches except for FCFC boundary condition. � Taylor & Francis Group, LLC.

In this paper, results of new infrared FIR-MIR measurements (wavenumber range of 4000–100 cm−1) in the range of the temperature 300 ÷ 8 K of the BiFeO3 ceramic are presented. Below 200 K only one symmetric band at ca. 800 cm−1 is visible. The full width at half maximum of this band decreases exponentially on cooling. The shape of the band at ca. 545 cm−1connected with A1 (TO) mode also changes between 60–40 K, this is in the vicinity of the phase transition at 50 K. Initially a broad band reveals its components as shoulder bands. Theirs FWHM decrease with cooling.

In the paper we present analytical calculations of the profiles and average values of the correlation radius of polarization fluctuations and generalized susceptibility in thin ferroelectric films with in-plane and out-of-plane polarization orientation. The contribution of polarization gradient, surface energy and depolarization field were taken into account. For the second order ferroelectrics the correlation radius and generalized susceptibility diverge at the film critical thickness as anticipated. The surface energy, inhomogeneous distribution of polarization and depolarization field related with incomplete screening govern the size effects such as thickness-induced phase transition, corresponding correlation radius and a generalized susceptibility divergence in the phase transition point.

This paper focuses on the design and fabrication of piezoelectric cantilevers and on the analysis of their bending, due to residual stress, as a function of growth parameters and geometrical features. The multilayered cantilevers consist of two top and bottom Molybdenum metals and an Aluminium nitride piezoelectric layer deposited onto a Polysilicon elastic layer using DC magnetron sputtering. After having optimized the growth parameters we fabricate cantilever arrays with different lengths and thicknesses of the Molybdenum and Aluminium nitride layers. The curvature of the fabricated cantilevers is determined by the tip deflection measured by scanning electron microscopy.

This paper consists of three major topics. The first topic is a review of challenges encountered in PZT thin film fabrication. Currently, sol-gel processing is one of the most promising techniques to fabricate PZT thin films. There are, however, several major challenges, including crack formation, thermally unstable electrodes, and poor piezoelectric properties. The second topic reveals some innovative fabrication processes that could substantially enhance quality of PZT thin films. For example, use of dilute sealant layer and rapid thermal annealing can lead to PZT films with large crack-free area. Use of sol electrophoretic deposition can enhance piezoelectric properties and thickness of PZT films simultaneously. Use of sol electrophoresis and soft lithography can directly pattern PZT films without etching. The third topic is design considerations encountered in the development of PZT thin-film microactuators. For example, one needs to confirm that the corner frequency of the PZT RC-circuit is much high...

This paper deals with the characterization of multi-layer actuators and bulk PZT ceramics under the influence of an applied electric field. The displacement profile of materials and devices with evaporated reflective dielectric layers was measured using a double-beam laser interferometer at room temperature. The displacements of 3 mm thick plates of bulk soft PZT were characterized to determine bulk material properties. The tested multi-layer actuator devices consisted of 20 layers, with each layer being 87 micrometers thick. The results of “point to point scanning” of displacement across piezoelectric materials are presented and the effective actuation area of the actuator displacement is determined. Comparisons are made of the behaviour of the bulk ceramics and the actuator. In addition to experimental measurement, representative coupled-field finite element model was constructed to compare with experimental x−y displacement data of multi-layer actuator.

Motivated by the observed thickness-scaling of the coercive field in ferroelectric films over five decades, we develop a statistical approach towards understanding the conceptual underpinnings of this behavior. Here the scaling exponent is determined by the field-dependence of a known and measured quantity, the nucleation rate per unit area. We end with a discussion of our initial assumptions and point to instances where they could no longer be applicable. *Paper originally presented at 10th European Meeting on Ferroelectricity, Cambridge, U.K., August 3–8, 2003.

Neutron diffraction was used to study the paraelectric (PE) to antiferroelectric (AFE) phase transition in a deuteron glass crystal Rb 0.5 (ND 4 ) 0.5 D 2 AsO 4 (DRADA-50). Coexistence of AFE and PE phases was proven in a temperature range 7-12 K wide. *Paper originally presented at 10th European Meeting on Ferroelectricity, Cambridge, U.K., August 3–8, 2003.

In this paper, nanoscale ferroelectric and piezoelectric properties (e.g. cartography of the piezoelectric coefficient after poling and polarisation direction) of sol-gel PZT thin films are studied using a modified Atomic Force Microscope (AFM). Polarisation patterns are created, and then imaged after more than one year. Hysteresis loops are recorded and it is shown that their shape and related parameters (remanent polarisation and coercitive field) are strongly dependant on the experimental conditions.

Molecular chirality leads to a wonderful variety of equilibrium structures, from the simple cholesteric phase to the twist-grain-boundary phases, and it is responsible for interesting and technologically important materials like ferroelectric liquid crystals. This paper will review some recent advances in our understanding of the connection between the chiral geometry of individual molecules and the important phenomenological parameters that determine macroscopic chiral structure. It will then consider chiral structure in columnar systems and propose a new equilibrium phase consisting of a regular lattice of twisted ropes., 20 pages with 6 epsf figures

The paper presents a new numerical approach for studying the thermodynamical and dynamical properties of finite spin-1/2 XY chains. Special attention is given to examining the influence of disorder on the average transverse dynamical susceptibility of Ising chain in random transverse field.

In the last few years, new techniques have been devised to measure optical rotation in cases where the linear birefringence dominates and this has opened up new fields of research into the phenomenon of optical rotation. In this paper, the phenomenon of optical rotation will be discussed with respect to our knowledge of crystal structure and a new measurement technique based on tilting of the crystal will be described.

While an insight into the mechanism of high temperature superconductivity is yet highly speculative, it is nowadays getting increasingly difficult to provide concrete experimental information about the magnetic nature of this elusive class of systems. Observation and interpretation of the magnetic origin of a phase, particularly through the technique of electron spin resonance (ESR), is found to have been highly inconsistent and controversial. In this paper we suggest that the Cu2+ signal from ions in the ∣x 2 − y 2> state does originate from the superconducting phase. From electron microscopic studies we find that the signal arises from Cu2+ −O2− −Cu2+ like interactions which are made possible by the formation of twins in a single crystal resulting in an overstoichiometry of oxygen at the twin boundaries. The observation of a strong ESR signal in the superconducting phase would then depend on the presence of twins and the extent of their distribution over the crystal.

This paper reviews the earlier experimental studies on light scattering in quartz near its phase transition, which ultimately laid the foundation for the basic concept of the soft mode. The theoretical work on the subject has been briefly referred to. A list of ferroelectrics in which soft mode studies have been carried out near TC using laser Raman spectroscopy is appended. Reference has also been made to the appearance of the central mode with abnormal increase in intensity at TC.