The Experts below are selected from a list of 5070 Experts worldwide ranked by ideXlab platform
C L Choy - One of the best experts on this subject based on the ideXlab platform.
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dipole alignment and Dielectric Susceptibility of defective ferroelectric monte carlo simulation
2005Co-Authors: Helen L W Chan, Junming Liu, K F Wang, S T Lau, C L ChoyAbstract:We present a Monte-Carlo simulation on the dipole alignment configuration and Dielectric Susceptibility of a defective ferroelectric lattice with randomly distributed lattice defects in the framework of the Ginzburg-Landau theory. These defects are assumed to suppress locally the electric dipoles. It is found that with increasing defect concentration the dipole lattice configuration evolves from a normal ferroelectric state to a two-phase coexisted state, where highly polarized regions are embedded in a paraelectric matrix. The Dielectric Susceptibility in lattices with various defect distributions is studied. The simulated results are used to explain the measured Dielectric response in ferroelectric copolymers containing defects induced by proton irradiation. (c) 2004 Elsevier B.V. All rights reserved.
Junming Liu - One of the best experts on this subject based on the ideXlab platform.
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dipole alignment and Dielectric Susceptibility of defective ferroelectric monte carlo simulation
2005Co-Authors: Helen L W Chan, Junming Liu, K F Wang, S T Lau, C L ChoyAbstract:We present a Monte-Carlo simulation on the dipole alignment configuration and Dielectric Susceptibility of a defective ferroelectric lattice with randomly distributed lattice defects in the framework of the Ginzburg-Landau theory. These defects are assumed to suppress locally the electric dipoles. It is found that with increasing defect concentration the dipole lattice configuration evolves from a normal ferroelectric state to a two-phase coexisted state, where highly polarized regions are embedded in a paraelectric matrix. The Dielectric Susceptibility in lattices with various defect distributions is studied. The simulated results are used to explain the measured Dielectric response in ferroelectric copolymers containing defects induced by proton irradiation. (c) 2004 Elsevier B.V. All rights reserved.
Arzdar Kiraci - One of the best experts on this subject based on the ideXlab platform.
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damping constant Dielectric Susceptibility inverse relaxation time and the activation energy calculated as a function of temperature from the raman frequency for the rhombohedral tetragonal phase transition in baceo3
2017Co-Authors: Arzdar Kiraci, Hamit YurtsevenAbstract:Temperature dependences of the damping constant (half width at half maximum), Dielectric Susceptibility, inverse relaxation time and the activation energy using the 110 cm -1 and 125 cm -1 Raman modes are calculated in the ferroelectric phase (T
Dielectric Susceptibility is also predicted through the observed frequencies of those Raman modes by using the Landau phenomenological theory. The values of the activation energy are also extracted from the damping constant as calculated from both models using the Raman modes studied in the ferroelectric phase of BaCeO 3 . -
damping constant Dielectric Susceptibility inverse relaxation time and the activation energy calculated as a function of temperature from the raman frequency for the rhombohedral tetragonal phase transition in baceo3
2017Co-Authors: Arzdar Kiraci, H. YurtsevenAbstract:Temperature dependences of the damping constant (half width at half maximum), Dielectric Susceptibility, inverse relaxation time and the activation energy of the 110 cm -1 and 125 cm -1 Raman modes are calculated in the ferroelectric phase (T
Dielectric Susceptibility is also predicted through the observed Raman frequencies of the modes studied by using the Landau phenomenological theory. Our calculated values of the inverse relaxation time and the Dielectric Susceptibility of the 110 cm -1 and 125 cm -1 Raman modes of BaCeO 3 can be compared with the experimental data when they are available in the literature. Finally, we extract the values of the activation energy from the damping constant calculated from both models for the Raman modes studied in the ferroelectric phase of BaCeO 3 . -
temperature dependence of the polarization Dielectric constant damping constant and the relaxation time close to the ferroelectric paraelectric phase transition in linbo3
2017Co-Authors: Arzdar Kiraci, Hamit YurtsevenAbstract:Abstract We calculate the order parameter (spontaneous polarization) and the inverse Dielectric Susceptibility at various temperatures in the ferroelectric phase of LiNbO3 for its ferroelectric-paraelectric phase transition (TC = 1260 K) using the Landau phenomenological model. For this calculation, the Raman frequencies of the soft optic mode (TO1) are used as the order parameter and the fitting procedure is employed for both the order parameter and the inverse Dielectric Susceptibility by means of the observed data from the literature. The temperature dependences of the damping constant and the inverse relaxation time are also computed using the pseudospin-phonon coupled model and the energy fluctuation model for the ferroelectric phase of LiNbO3. The activation energy is deduced from the damping constant for both models studied and compared with the k B T C value of LiNbO3. We find that the order parameter (Raman frequency of the TO1 mode) and the inverse Dielectric Susceptibility decrease with increasing temperature, as expected from the mean field model. We also find that the damping constant and the inverse relaxation time of this soft mode increases and decreases, respectively, with increasing temperature on the basis of the two models studied in the ferroelectric phase of LiNbO3. This indicates that our method of calculation is satisfactory to describe the observed behaviour of the ferroelectric-paraelectric phase transition in LiNbO3.
A K Tagantsev - One of the best experts on this subject based on the ideXlab platform.
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giant domain wall contribution to the Dielectric Susceptibility in batio3 single crystals
2007Co-Authors: Yeliang Wang, A K Tagantsev, Dragan Damjanovic, N SetterAbstract:Giant domain wall contribution to the Dielectric Susceptibility was observed in the rhombohedral phase of BaTiO3 single crystals. The unusual contribution can be two orders of magnitude larger than the thermodynamically estimated lattice Susceptibility, even at driving fields that are much smaller than the coercive field. Nonlinearity measurements suggest a local sliding motion of depinned domain walls being responsible for the ultrahigh Susceptibility. Pretreatments, particularly those performed in high temperature ferroelectric phases, can strongly affect the contribution of this local sliding mechanism.
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phenomenological model of dynamic nonlinear response of relaxor ferroelectrics
2000Co-Authors: A E Glazounov, A K TagantsevAbstract:A phenomenological model was proposed which describes frequency dispersion of nonlinear Dielectric response of relaxer ferroelectrics (relaxors) as a result of dispersion of their linens Dielectric permittivity. The model was applied to Pb(Mg1/3Nb2/3)O-3 (PMN) relaxer. It provided a good qualitative description of temperature and frequency dependence of the third harmonics of PMN. Analysis within the model yielded a frequency independent nonlinear coefficient corresponding: to static nonlinear Dielectric Susceptibility. The model explained the recently reported for PMN data on the Vogel-Fulcher law for frequency dependence of the temperature at which the third harmonics passes a maximum.
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does freezing in pbmg1 3nb2 3o3 relaxor manifest itself in nonlinear Dielectric Susceptibility
1999Co-Authors: A K Tagantsev, A E GlazounovAbstract:A possible anomaly in the temperature dependence of nonlinear Dielectric Susceptibility chi(nl) of relaxor ferroelectrics related with the freezing phase transition was investigated. First, based on the phenomenological approach, the anomaly in the chi(nl) was analyzed, including its shape, sign, and crystalline anisotropy. Second, the theoretical results were applied to the analysis of experimental data on nonlinear Dielectric permittivity of single crystals of PbMg1/3Nb2/3O3 (PMN) relaxor. It was concluded that in contrast to earlier publications, there is no evidence for the anomaly in chi(nl)(T) of PMN related with the freezing transition. (C) 1999 American Institute of Physics.
Helen L W Chan - One of the best experts on this subject based on the ideXlab platform.
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dipole alignment and Dielectric Susceptibility of defective ferroelectric monte carlo simulation
2005Co-Authors: Helen L W Chan, Junming Liu, K F Wang, S T Lau, C L ChoyAbstract:We present a Monte-Carlo simulation on the dipole alignment configuration and Dielectric Susceptibility of a defective ferroelectric lattice with randomly distributed lattice defects in the framework of the Ginzburg-Landau theory. These defects are assumed to suppress locally the electric dipoles. It is found that with increasing defect concentration the dipole lattice configuration evolves from a normal ferroelectric state to a two-phase coexisted state, where highly polarized regions are embedded in a paraelectric matrix. The Dielectric Susceptibility in lattices with various defect distributions is studied. The simulated results are used to explain the measured Dielectric response in ferroelectric copolymers containing defects induced by proton irradiation. (c) 2004 Elsevier B.V. All rights reserved.
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monte carlo simulation of the Dielectric Susceptibility of ginzburg landau mode relaxors
2004Co-Authors: J M Liu, Xiaomu Wang, Helen L W Chan, Chungloong ChoyAbstract:The electric dipole configuration and Dielectric Susceptibility of a Ginzburg-Landau model ferroelectric lattice with randomly distributed defects are simulated using the Monte Carlo method. The simulated characteristics of the lattice configuration and Dielectric Susceptibility indicate that the model lattice evolves from a normal ferroelectric state to a typical relaxor state with increasing defect concentration. Consequently, the energy and Dielectric Susceptibility characteristics associated with the ferroelectric phase transitions become smeared. The simulated results approve the applicability of the Ginzburg-Landau model in approaching relaxor ferroelectrics.