OS1209 Theoretical study on structure and formation process of domain walls in ferroelectric material

2013 ◽  
Vol 2013 (0) ◽  
pp. _OS1209-1_-_OS1209-2_
Author(s):  
Akira Goto ◽  
Kazuaki Toyoura ◽  
Atsutomo Nakamura ◽  
Katsuyuki Matsunaga
2006 ◽  
Author(s):  
Chad M. Landis

The overall objective of this work is to develop a theoretical model that can track the evolution of the domain structures in ferroelectric crystals, which are responsible for the non-linear electromechanical behavior of these materials. To this end, a continuum thermodynamics framework is devised, and the theory falls into the class of phase-field or diffuse-interface modeling approaches. Here a set of micro-forces and governing balance laws are postulated and applied within the second law of thermodynamics to identify the appropriate material constitutive relationships. The approach is shown to yield the commonly accepted Ginzburg-Landau equation for the evolution of the polarization order parameter. Within the theory a form for the free energy is postulated that can be applied to fit the general elastic, piezoelectric and dielectric properties of a ferroelectric material near its spontaneously polarized state. Thereafter, a principle of virtual work is specified for the theory and is implemented to devise a finite element formulation. The theory and numerical methods are used to investigate the interactions of 180° and 90° domain walls with an array of charge defects and to determine the electromechanical pinning strength of the array on the walls.


2020 ◽  
Vol 11 ◽  
Author(s):  
Cleber Barbosa da Silva Clarindo ◽  
Stella Miller ◽  
Érika Christina Kohle

The main purpose of this article is to discuss the development of capacities linked to theoretical thinking during the formation process of Learning Activity in students of the early years of elementary school. It considers some elements which could form the basis for thinking about teaching activity as a means of conducting students toward that development. It starts from the hypothesis that the development of the capacities of analysis, reflection, and mental planning depends, essentially, on the systematic organization of the principles and ways of action of the students on the theoretical contents in their learning process. The hypothesis further states that Learning Activity is the most appropriate way to organize pedagogical work for the development of methods of action that would enable students to achieve new higher psychological formations and develop new ways of thinking and acting in the learning environment. The theoretical study was carried out through locating, gathering, analyzing, synthesizing, and reframing the theorical ideas contained in publications, texts, articles, and books by authors of the Cultural-Historical Theory. The study places emphasis on Learning Activity as an adequate way to develop psychic neoformations in school-age children, since their organization, based on the solution of learning tasks through learning actions, is the source of the development of analysis, reflection, and mental planning skills, as constituent parts of theoretical thinking in school-age children.


2018 ◽  
Vol 33 (1) ◽  
pp. 1-13
Author(s):  
张 晶 ZHANG Jing ◽  
周 璇 ZHOU Xuan ◽  
陈思博 CHEN Si-bo ◽  
刘 凯 LIU Kai ◽  
张志东 ZHANG Zhi-dong

2019 ◽  
Vol 27 (26) ◽  
pp. 38326 ◽  
Author(s):  
Monali Suar ◽  
Oliver Melchert ◽  
Maik Rahlves ◽  
Bernhard Roth

2017 ◽  
Vol 677 ◽  
pp. 13-18 ◽  
Author(s):  
Vitória S. Reis ◽  
Eliziane S. Santos ◽  
Daniela N.F. Bonsolhos ◽  
Luciana Guimarães ◽  
Wagner B. De Almeida ◽  
...  

2012 ◽  
Vol 86 (2) ◽  
Author(s):  
László Balogh ◽  
Krisztián Palotás ◽  
László Udvardi ◽  
László Szunyogh ◽  
Ulrich Nowak

Sign in / Sign up

Export Citation Format

Share Document