相场模拟应变调控PbZr(1-x)TixO3薄膜微观畴结构和宏观铁电性能  

Phase field simulation of misfit strain manipulating domain structure and ferroelectric properties in PbZr(1-x)TixO3 thin films

作　　者：刘迪 王静 王俊升 黄厚兵 Liu Di;Wang Jing;Wang Jun-Sheng;Huang Hou-Bing(School of Materials Science and Engineering,Beijing Institute of Technology,Beijing 100081,China;Advanced Research Institute of Multidisciplinary Science,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]北京理工大学材料学院,北京100081 [2]北京理工大学前沿交叉科学研究院,北京100081

出　　处：《物理学报》2020年第12期306-315,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51972028);国家重点基础研究发展计划(批准号:2019YFA0307900)资助的课题。

摘　　要：外延生长铁电薄膜中基底失配应变能够调控微观铁电畴结构和宏观铁电性能.本文选择了三种相结构(四方相、四方和菱方混合相、菱方相)PbZr(1–x)TixO3(x=0.8,0.48,0.2)铁电薄膜,利用相场模拟研究了在不同基底失配应变(esub)作用下,三种成分铁电薄膜中微观畴结构的演化以及宏观极化-电场回线.随着应变从–1.0%变化到1.0%,三种相结构铁电薄膜的矫顽场、饱和极化值以及剩余极化值全都降低,其中PbZr0.52Ti0.48O3薄膜的饱和极化值和剩余极化值比另外两种薄膜降低更快.模拟结果表明拉应变能提高铁电薄膜储能效率,其中准同型相界处应变提升储能效率最快.本工作揭示了应变对PbZr(1–x)TixO3铁电薄膜中畴结构、电滞回线以及储能等方面的影响,为铁电功能薄膜材料的实验设计提供了理论基础.Ferroelectric domain structures and ferroelectric properties in the hetero-epitaxially constrained ferroelectric thin films can be manipulated by substrate misfit strain.In this work,three kinds of phase structures of PbZr(1–x)TixO3 thin films,including tetragonal,tetragonal-rhombohedral-mixed and rhombohedral phases,are investigated.Firstly,the ferroelectric domain structures at different substrate misfit biaxial strains are obtained by the phase-field simulation.Then we calculate the polarization-electric field hysteresis loops at different misfit strains,and obtain the coercive field,saturation polarization,and remnant polarization.In the tetragonal PbZr(1–x)TixO3(x=0.8)thin film,compressive strain contributes to the formation of out-of-plane c1/c2 domain,and tensile strain favors in-plane a1/a2 domain formation.With the increase of compressive strain,the tetragonal phase and the rhombohedral phase coexist in PbZr(1–x)TixO3(x=0.48)film near the morphotropic phase boundary,while the tensile strain reduces the rhombohedral domain size.In the rhombohedral PbZr(1–x)TixO3(x=0.2)film,the rhombohedral domains are steady states under compressive strain and tensile strain.As the misfit strain changes from–1.0%to 1.0%,the value of the coercive field,saturation polarization and remnant polarization decrease.Among them,for tetragonal-rhombohedral mixed phase,the reductions of saturation field and remnant polarization are larger than for tetragonal phase and rhombohedral phase.The coercive field of mixed phase decreases rapidly under the compressive strain,but deceases slowly under the tensile strain.It is worth noting that the remnant polarization decreases faster than the saturation polarization in three components of ferroelectric thin film.Due to the electromechanical coupling,when x=0.48 at the morphotropic phase boundary it is shown that the remnant polarization reduction is faster than those of the other two types of ferroelectric thin films,and the small coercive field is obtained in the case of large ten

关 键 词：相场模拟 失配应变 铁电畴 电滞回线 

分 类 号：TB383.2[一般工业技术—材料科学与工程] TM221[电气工程—电工理论与新技术]