氧气退火对(In+Nb)共掺杂TiO_2陶瓷的介电性能的影响  

Effect of oxygen annealing on dielectric properties of (In+Nb) doped TiO_2 ceramics

作　　者：赵小刚[1] 刘鹏[1] 

机构地区：[1]陕西师范大学物理学与信息技术学院,西安710062

出　　处：《科学通报》2017年第25期2967-2976,共10页Chinese Science Bulletin

基　　金：国家自然科学基金(51572162);陕西师范大学优秀博士学位论文(S2012YB05)资助

摘　　要：以固相法制备的(In_(1/2)Nb_(1/2))_(0.05)Ti_(0.95)O_2陶瓷为研究对象,研究了氧气退火对晶体结构、显微组织以及介电性能等的影响,探讨了产生高介电常数的起源.结果表明氧气退火降低了(In_(1/2)Nb_(1/2))_(0.05)Ti_(0.95)O_2陶瓷的介电损耗.在介电温、频谱上观察到3种介电弛豫过程.采用普适弛豫定律,分析了局域化电子与缺陷团簇的偶极极化、极化子跳跃极化和界面极化对介电弛豫的贡献,提出了在(In+Nb)掺杂TiO_2的高介电陶瓷材料中极化子跳跃极化对高介电有贡献.Colossal dielectric constant materials have been attracting great attention for their applications in myriad types of miniaturized devices and high-energy-density storage fields.With the demand of size miniaturization in many microelectronic devices,colossal dielectric constant oxides have become essential for modern microelectronic devices,such as dynamic random access memory（DRAM） devices and on-chip capacitors.Recently,in order to obtain the high dielectric permittivity,but with acceptable dielectric loss and less frequency/temperature dependence,the introduction of localized lattice defect states is proposed.Using Nb^（5＋） as electron-donors and In^（3＋） as electron-acceptors is doped into rutile TiO_2.And the reduction of Ti^（4＋） ions is affected by the electron-acceptors in the local lattice defect clusters.Thus,the extraordinary colossal permittivity with low dielectric loss over a wide range of frequency and temperature is attributed to the electron-pinned defect-dipoles.There may be complex effects on the origin of novel colossal permittivity properties.In this work,（In_（1/2）Nb_（1/2））TiO_2 ceramics are prepared by the solid state reaction method,and the dielectric properties are studied.Starting materials（TiO_2,In_2O_3,and Nb_2O_5 99.99%） are weighed as the composition（In_（1/2）Nb_（1/2））_（0.05）Ti_（0.95）O_2.The weighed batches are mixed,calcined,and pressed into disks.Finally,the samples are sintered at 1673 K for 10 h in air,and then some samples are annealed at 1273 K for 5 h in O_2 atmosphere（purity 99.99%）.The density of the sintered ceramics is initially measured using the geometrical method and then the Archimedes method.The microstructure of the sintered ceramics is investigated with a field electron gun scanning electron microscope（FEI Nova Nano-SEM 450）.X-ray diffraction is performed on a Rigaku D/max 2250 diffractometer（Japan） with Cu Ka radiation（40 kV and 50 mA）.The data for all the samples are measured with a slow scanning

关 键 词：TIO2 巨介电常数 介电弛豫 

分 类 号：TQ174.1[化学工程—陶瓷工业]