不同表面层铁电薄膜的相变理论研究  

Theoretical Study on Phase Transition of Ferroelectric Thin Films with Different Surface Layers

作　　者：杨焕银[1,2] 郭红力 孙红娟[2] 彭同江[2] YANG Huanyin;GUO Hongli;SUN Hongjuan;PENG Tongjiang(Yangtze Normal University,Fuling 408100,China;Key Laboratory of Ministry of Education for Solid Waste Treatment and Resource Recycle,Southwest University of Science and Technology,Mianyang 621010,China)

机构地区：[1]长江师范学院,涪陵408100 [2]西南科技大学,固体废物处理与资源化教育部重点实验室,绵阳621010

出　　处：《人工晶体学报》2020年第9期1604-1608,1619,共6页Journal of Synthetic Crystals

基　　金：西南科技大学2017年龙山学术人才科研支持团队项目(17LZXT11);教育部春晖计划(Z2016172);长江师范学院青年项目(2017XJQN02)。

摘　　要：基于横场伊辛模型,利用平均场近似理论推导久期方程的解,研究了单、双表面层铁电薄膜在不同总层数时,系统表面交换相互作用和内、外横场参量对铁电-顺电相变的影响,讨论了铁电薄膜各交换相互作用和横场参数以及薄膜层数对单、双表面铁电薄膜相图的影响,并计算了各个相互作用参数的过渡值特性。研究结果表明:薄膜总层数n、表面层数、内外部横场、表面交换相互作用都会改变铁电薄膜的相图。利用薄膜的尺寸效应和表面效应,增大系统总层数、表面层数和表面交换相互作用,可以提高薄膜相变温度,扩大铁电相区域,从而有利于改善铁电功能器件的环境温度。Based on the Transverse Ising Model,the solution of the duration equation is derived using the Mean-Field approximation theory.The effects of exchange interactions on the surface of the system and the internal and external transverse field parameters on the ferroelectric-paraelectric phase transition were studied for single and double surface ferroelectric films with different total layers.The effects of various exchange interactions and transverse field parameters of ferroelectric thin films on the phase diagrams of single and double surface ferroelectric thin films were discussed.The results show the total number of thin films layers n,the number of surface layers,internal and external transverse fields,and surface exchange interactions will change the phase diagram of ferroelectric thin films.Using the size effect and surface effect of the film,increasing the total number of layers,surface layers and surface exchange interactions of the system can increase the phase transition temperature of the films and expand the ferroelectric phase area,which is conducive to improving the ambient temperature of the ferroelectric functional device.

关 键 词：铁电薄膜 相变 横场 交换相互作用 尺寸效应 表面效应 

分 类 号：O469[理学—凝聚态物理]