Microscopic model of domain wall motion

Abstract

Articles you may be interested inPolarization reversal and jump-like domain wall motion in stoichiometric LiTaO3 produced by vapor transport equilibration J. Appl. Phys. 111, 014101 (2012); 10.1063/1.3673601Correlated motion dynamics of electron channels and domain walls in a ferroelectric-gate thin-film transistor consisting of a ZnO/Pb(Zr,Ti)O3 stacked structure Polarization switching is simulated using a model based on a sequence of single dipole flips. The single dipole flips are assumed to be thermally activated with transition rates depending on the local field. The time to switch a single dipole depends on the deterministic transition rate and on a probabilistic factor. In each step, the dipole with the shortest flip time is switched. We investigate one dimensional dipole chains as well as two and three dimensional systems based on the barium titanate structure that comprises single charges fluctuating in double well potentials and induced dipoles. The two and three dimensional simulations yield intrinsic dead layers close to the electrodes that can not be switched even in very strong fields. These non switchable layers are nuclei for the domain wall motion and thus nuclei for the switching process. The switching time of the system decreases faster than exponential for low fields with increasing field. This decrease slows down for higher fields. Furthermore, we found intrinsic dead layers around a defect. V C 2014 AIP Publishing LLC. [http://dx.

Kinetic Monte Carlo simulations of organic ferroelectrics

“…More generally, the model itself could be adapted to study other ferroelectric systems, such as BTO or PVDF. 8,38 For inorganic ferroelectrics however, one should take into account an elastic term that penalizes domain wall formation, which will increase the computational complexity. Since the model works for any fixed morphology, including irregular ones, systems with extended disorder, such as dipolar glasses, could also be investigated although any increase in the degrees of freedom will come at the cost of increased computation times.…”

Experimental Characterization of Ferroelectric Capacitor Circuits for the Realization of Simply Designed Electroceuticals

“…In contrast, for circuit topologies consisting of strongly voltage-dependent capacitors, the dynamic behavior of the system cannot be modeled properly for higher AC voltages. In other words, the measurement of voltage-dependent capacitors in Section 2.1 does not include the complex ferroelectric switching dynamics that occur at higher AC voltages and frequencies of inductive power transfer [35].…”

Interplay of domain structure and phase transitions: theory, experiment and functionality

“…It is common belief that the formation of nuclei in the homogeneous medium (homogeneous or intrinsic nucleation) is not the most frequent mechanism in real materials as the energy for nucleation may be reduced locally (heterogeneous or extrinsic nucleation) at (1) point defects [304,305], (2) concentration inhomogeneities in solid solutions [306], (3) electrodes [307,308] (4) surfaces and defects at surfaces [303], (5) dislocations, cracks, pores and other defects, (6) domain walls [240,286] (in case of field-induced switching and FE-FE transitions) which are typically centers of excess charges, stress accumulation, modified energy landscapes, and frustrations [309]. The nucleation barrier may thus be locally reduced [272,273,310], and depends on the materials' defect structure and the boundary conditions.…”