Nb掺杂对BaTi_(0.98)Fe_(0.02)O_3陶瓷介电性能的影响  

Effects of Nb doping on dielectric properties of BaTi_(0.98)Fe_(0.02)O_3 ceramics

作　　者：李常昊[1] 丁士华[1] 张晓云 宋天秀[1] 黄龙 LI Changhao;DING Shihua;ZHANG Xiaoyun;SONG Tianxiu;HUANG Long(School of Materials Science and Engineering,Xihua University,Chengdu 610039,China)

机构地区：[1]西华大学材料科学与工程学院,四川成都610039

出　　处：《电子元件与材料》2018年第6期6-12,共7页Electronic Components And Materials

基　　金：国家自然科学基金资助(11074203)

摘　　要：以Ba Ti_(0.98)Fe_(0.02)O_3陶瓷为基体,采用传统固相反应法制备Ba Ti_(0.98-x)Fe_(0.02)Nb_xO_3(0≤x≤0.08)陶瓷样品。通过XRD、SEM、LCR分析仪以及GULP软件对陶瓷样品的结构、介电性能以及缺陷构型和能量进行了分析。结果表明:Nb掺杂使陶瓷样品由四方相和六方相钛酸钡并存向四方相钛酸钡转变,出现第二相Ba_6Ti_(17)O_(40),Nb掺杂量未超过0.02时,陶瓷样品四方率增大;Nb掺杂一定程度上有细化晶粒的作用;介电峰峰值温度(T_m)随着Nb掺杂量的增大向低温方向移动,介电常数先增大后减小,当Nb掺杂量超过0.04时出现弛豫现象;通过分子动力学缺陷模拟表明陶瓷样品中主要存在的缺陷是钡空位、氧空位以及异价离子占位等形成的复合缺陷,随Nb掺杂量的增大,陶瓷样品中缺陷偶极子浓度逐渐增大,极性纳米微区(PNRs)逐渐增多,弛豫程度增大。The Ba Ti（0.98）Fe（0.02）NbxO3（ 0≤x≤0. 08） ceramics were prepared by conventional solid state reaction processing.The crystal structure and dielectric properties of ceramic samples were studied by XRD,SEM,LCR analyzer. Defects configuration and defects energies were investigated by GULP software. The results indicate that ceramics transform from hexagonal to tetragonal barium titanate with Nb doping content increasing,meanwhile,the second phase（ Ba6 Ti（17） O（40）） appears and tetragonality increases when x≤0. 02. With the increase of Nb concentration,the dielectric peak temperature shifts to lower temperature,and the relaxation is observed when x≥0. 04. The dielectric constant increases first when x≤0. 02,and then decreases when x≥0. 03. The main defects are barium vacancies,oxygen vacancies,and complex defects formed by substitutional isovalentions in Ba Ti（0.98）Fe（0.02）NbxO3 ceramics by molecular dynamics defect simulation. With Nb doping content increasing,the concentration of defect dipoles,polar nanoregions（ PNRs）,and relaxation degree increase.

关 键 词：BaTiO_3陶瓷 Nb掺杂 固相反应 介电性能 缺陷偶极子 弛豫铁电体 

分 类 号：TM22[一般工业技术—材料科学与工程]