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Full-Text Articles in Physical Sciences and Mathematics

Static And Dynamical Properties Of Ferroelectrics And Related Material In Bulk And Nanostructure Forms, Zhigang Gui Jul 2015

Static And Dynamical Properties Of Ferroelectrics And Related Material In Bulk And Nanostructure Forms, Zhigang Gui

Graduate Theses and Dissertations

Ferroelectrics (FE) and multiferroics (MFE) have attracted a lot of attentions due to their rich and novel properties. Studies towards FE and MFE are of both fundamental and technological importance. We use a first-principles-based effective Hamiltonian method, conventional ab-initio packages and linear-scale three-dimension fragment method to investigate several important issues about FE and MFE. Tuning the properties of FE and MFE films are essential for miniaturized device applications, which can be realized through epitaxial strain and growth direction. In this dissertation, we use the effective Hamiltonian method to study (i) BaTiO 3 films grown along the (110) pseudocubic direction on …


Modeling And Simulation Of Microstructures, Mechanisms, And Diffraction Effects In Energy Materials: Ferroelectrics And Lithium Ion Battery Cathode Materials, Jie Zhou Jan 2015

Modeling And Simulation Of Microstructures, Mechanisms, And Diffraction Effects In Energy Materials: Ferroelectrics And Lithium Ion Battery Cathode Materials, Jie Zhou

Dissertations, Master's Theses and Master's Reports - Open

Ferroelectric materials, as a large family exploited for the application of sensors, transducers and random access memories, open up a remarkable ground both for fundamental science and industry. Dielectric and piezoelectric properties are of the most interest in ferroelectric materials, which motivate research to enhance ferroelectric properties based on various application purposes. Among the multitudinous candidates in ferroelectric family, pseudo binary solid solutions with ABO3 lattice structure attract special attention in virtue of their large strain response when applying external loading. Furthermore, existence of morphological phase boundary (MPB) on their phase diagrams shed light on tuning material compositions to …


Acousto-Electric Impedance Of Ferroelectric Phononic Superlattice, Ola Hassan Nusierat Jan 2015

Acousto-Electric Impedance Of Ferroelectric Phononic Superlattice, Ola Hassan Nusierat

Electronic Theses and Dissertations

The Acousto-Electric Impedance z of a Ferroelectric Phononic Superlattice (fps) is investigated. The analytical derivation of z and its phase reveal that both are functions of physical parameters such as the electromechanical coupling coefficient, the mechanical quality factor, the domain length and the phase velocity of the plate acoustic waves (paw). Mathematical code is produced that allows for modeling z in a two dimensional fps. It is observed that z depends on the number of domains in the fps structure. Fewer domains in the structure might minimize z or make it approach zero at certain conditions. A series of experiments …