铁电颗粒的尺寸效应

SIZE EFFECT OF FERROELECTRIC PARTICLE DESCRIBED BY TRANSVERSE ISING MODEL WITH LONG-RANGE INTERACTION

应用具有长程相互作用的横场伊辛模型模拟了铁电颗粒 ,考察了尺寸和长程相互作用对铁电颗粒的极化和相变的影响 .我们得到的结论是 :1.随着铁电颗粒尺寸的减小和长程相互作用的增强 ,铁电颗粒的相变温度降低 .同时发现铁电颗粒存在一个临界尺寸 ,当铁电颗粒的尺寸小于临界尺寸时 ,铁电颗粒将不会有铁电相到顺电相的相变 ,且此临界尺寸随长程相互作用的增强而变大 .2 .随着长程相互作用的增强 ,铁电颗粒的极化强度增大 ,在相同的条件下 ,晶格中心点的极化强度总是大于晶格边上的格点的极化强度 .

The transverse Ising model with long range interaction in a simple subic lattice is used to simulate a ferroelectric particle. The size and long range interaction effects on the phase transition and the polarization of the ferroelectric particle are discussed. We obtain the phase transiton temperature of the ferroelectric particle decreases with the decreasing of the size of the particle. There exists a critical size, below which the ferroelectric phase can not occur, increases with the increasing of the long range interaction. The polarization goes up with the increasing of the long range interaction, and the polarization of the center site in the lattice is larger than that of the corner site under the same condition.