铁电纳米颗粒相变中的尺寸效应  

Size Effect in Ferroelectric Nanoparticles Phase Transition

作　　者：朱道佩 晏浩城 田思远 ZHU Dao-pei;YAN Hao-cheng;TIAN Si-yuan(School of Civil And Surveying & Mapping Engineering, Jiangxi University of Science and Technology (Nanchang), Nanchang 330013, China)

机构地区：[1]江西理工大学土木与测绘工程学院(南昌),南昌330013

出　　处：《科学技术与工程》2022年第5期1995-2001,共7页Science Technology and Engineering

基　　金：2019年度江西省教育厅科学技术研究项目(GJJ190497);江西理工大学高层次人才科研启动项目(jxncbs19009)。

摘　　要：由铁电纳米颗粒和介电质基体组成的复合材料具有很多功能特性,这些特性可广泛用于新型电子和能量收集装置。然而,铁电颗粒的形状、尺寸和在介电质基体中的取向对这些功能的影响还没有被研究清楚。利用一种中尺度建模方法,模拟了具有极性、弹性和热自由度的铁电纳米复合材料的性质,以及这些性质对尺寸、形状和取向的依赖性。基于时间依赖的朗道金兹堡理论,应用多物理场耦合的有限元方法模拟了嵌入介电质中的孤立PbTiO_(3)或BaTiO_(3)纳米颗粒中的极化行为。从模拟结果可知,铁电纳米颗粒的尺寸和材料以及周围电介质的材料都会对平衡极化场产生影响。对于不同尺寸和材料参数的组合,极化场表现为单畴、涡旋畴和多畴状态。模拟结果还表明存在一个临界尺寸,低于该尺寸时铁电性消失。对于PbTiO_(3)和BaTiO_(3)颗粒,该尺寸分别为3.3 nm和4.8 nm。Composite materials comprised of ferroelectric nanoparticles in a dielectric matrix have a variety of functional properties attractive for a wide range of novel electronic and energy harvesting devices.However,the effects of the shape,size and orientation of ferroelectric particles in dielectric matrix on these functions have not been clearly studied.A mesoscale modeling method was used to simulate the properties of ferroelectric nanocomposites with polar,elastic and thermal degrees of freedom,and the dependence of these properties on size,shape and orientation.Based on the time-dependent Ginzburg-Landau theory,the polarization behavior of isolated PbTiO_(3) or BaTiO_(3) nanoparticles embedded in dielectric was simulated by using the finite element method coupled with multiple physical fields.The simulation results show that the size and material of ferroelectric nanoparticles and the surrounding dielectric materials will affect the equilibrium polarization field.For the combination of different sizes and material parameters,the polarization field shows single domain,vortex domain and multi domain.The simulation results also show that there is a critical size below which the ferroelectricity disappears.For PbTiO_(3) and BaTiO_(3) particles,the size is 3.3 nm and 4.8 nm,respectively.

关 键 词：铁电材料 电畴 涡旋态 畴壁 多畴 

分 类 号：TQ174.1[化学工程—陶瓷工业]