不同元素掺杂的烧绿石材料介电性质研究

On the Dielectric Properties of Pyrochlore Doped with Different Elements

研究经过Co、Sn和Ni三种元素分别掺杂后的呼吸烧绿石材料LiInCr_(3.9) M_(0.1) O_(8)(M=Cr,Sn,Ni)的微观结构和介电性质。用传统固相反应法制备了多晶呼吸烧绿石材料LiInCr_(3.9) M_(0.1) O_(8)(M=Co,Sn,Ni),用X线衍射仪对样品结构和相纯度进行研究并用Fullprof软件对XRD数据进行精修,用场发射扫描电子显微镜对样本的晶粒形貌和尺寸进行分析,用宽频介电测试仪(20Hz-10MHz)测定了其介电性质。结果表明有被掺杂后的样品纯度较高并且保留了空间群F-43m的立方晶系。从介电常数、介电损耗、阻抗谱虚部、电模量虚部随频率变化的曲线图中都可以发现明显的驰豫峰。由此得出结论复阻抗图可以看出驰豫现象来源于晶界效应。高频率区域(1000kHz-10000kHz)介电损耗在1.0到0.1之间,结果表明被掺杂后的材料在更高频段具有潜在的应用价值。

The microstructure and dielectric properties were studied after LiInCr_(3.9) M_(0.1) O_(8)(M=Co,Sn,Ni)respirable pyrochlore was doped with Co,Sn and Ni.The polycrystalline respirable pyrochlore material LiInCr_(3.9) M_(0.1) O_(8)(M=Co,Sn,Ni)was prepared by traditional solid state reaction method.The structure and phase purity of the sample were studied by X-ray diffractometer,and the XRD data was refined by Fullprof software.The grain morphology and size of the sample were analyzed by field emission scanning electron microscope,and its dielectric properties were measured by a broadband dielectric tester(20Hz~10MHz).The results show that all the doped samples have high purity and retain the cubic crystal system of space group F-43m.From the curves of dielectric constant,dielectric loss,imaginary part of impedance spectrum and imaginary part of electrical modulus changing with frequency,obvious relaxation peaks can be found.It can be concluded from the complex impedance diagram that the relaxation phenomenon originates from the grain boundary effect.The dielectric loss in the high frequency region(1000~10000kHz)is between 1.0 and 0.1.The results show that the doped materials have potential application value in higher frequency band.