TbCrO_(3)的合成以及磁、介电性能研究  

Synthesis magnetic and dielectric properties of TbCrO_(3)

作　　者：樊利国 王松伟[1,2] 张亚乐 杨瑞鑫 崔梦范 张鑫[1,2] FAN Liguo;WANG Songwei;ZHANG Yale;YANG Ruixin;CUI Mengfan;ZHANG Xin(School of Materials Science and Engineering,Guilin University of Electronic Technology,Guilin 541004,China;Guangxi Key Laboratory of Information Materials,Guilin University of Electronic Technolog,Guilin 541004,China)

机构地区：[1]桂林电子科技大学材料科学与工程学院,广西桂林541004 [2]桂林电子科技大学广西电子信息材料构效关系重点实验室,广西桂林541004

出　　处：《桂林电子科技大学学报》2022年第4期333-338,共6页Journal of Guilin University of Electronic Technology

基　　金：广西电子信息材料构效关系重点实验室基金(191004-Z,201020-Z,201021-Z)。

摘　　要：为研究TbCrO_(3)低温下的磁相变和介电弛豫,采用溶胶凝胶自蔓延燃烧合成法制备了TbCrO_(3)材料,并对其磁、电性能进行了分析。利用X射线衍射仪、场发射扫描电子显微镜和综合物性测量系统对材料进行了物相和物性表征。X射线衍射结果表明,合成的TbCrO_(3)为单相多晶样品,空间群为Pbnm;直流磁化曲线表明,材料的奈尔温度T N=162 K,分子的有效磁矩理论值与通过磁化曲线高温顺磁段外推得到的实验值相吻合,说明样品的磁性遵循居里外斯定律,外斯常数为负值(-32.2 K),表明样品内部的反铁磁耦合特性;介电测量中,在低频、高温下,样品出现了介电色散和巨介电常数,归因于空间电荷极化。样品在200 K附近出现介电驰豫,损耗峰随着频率增大向高温移动,拟合出的活化能为0.358 eV,这与RCrO_(3)体系中其他样品的活化能接近。根据介电常数虚部与频率关系分析出驰豫为麦克斯韦-瓦格纳驰豫,由阻抗谱分析出驰豫是由晶界与晶粒共同作用的。TbCrO_(3)在低温下存在顺磁-反铁磁相变,介电弛豫显示出热激活行为。In order to study the magnetic phase transition and dielectric relaxation of TbCrO_(3)at low temperature,TbCrO_(3)samples were prepared by the sol-gel self-propagating combustion synthesis method,and its magnetic and electrical properties were analyzed.The crystal structue and physical properties of TbCrO_(3)were characterized by X-ray diffractometer,field emission scanning electron microscope and physical property measurement system,respectively.X-ray diffraction results show that the synthesized TbCrO_(3)is single with Pbnm space group.The DC magnetization curve shows that the Neel temperature of the material is T N=162 K,the theoretical value of the effective magnetic moment of the molecule is consistent with the experimental value obtained by extrapolation of the high-temperature paramagnetic section of the magnetization curve,indicating that the magnetic properties of the sample follow Curie′s law,the Weiss constant is negative(-32.2 K),indicating the antiferromagnetic coupling characteristics inside the sample.In the dielectric measurement,at low frequency and high temperature,the sample has dielectric dispersion and giant dielectric constant,which is attributed to space charge polarization.The sample shows dielectric relaxation near 200 K,and the loss peak moves to high temperature with increasing frequency.The fitted activation energy is 0.358 eV,which is close to the activation energy of other samples in the RCrO_(3)system.According to the relationship between the imaginary part of the dielectric constant and the frequency,the relaxation is the Maxwell-Wagner relaxation.From impedance spectroscopy analysis,relaxation is caused by the interaction of grain boundaries and grains.TbCrO_(3)has a paramagnetic-antiferromagnetic phase transition at low temperature,and dielectric relaxation shows thermal activation behavior.

关 键 词：溶胶凝胶自蔓延燃烧 反铁磁 巨介电常数 空间电荷极化 介电弛豫 

分 类 号：TB34[一般工业技术—材料科学与工程]