低温烧结Bi取代钇铁石榴石的复阻抗研究

Electrcal Investigation of Bi-substituted Yttrium Iron Garnet Using Complex Impedance Spectroscopy

用复阻抗的方法研究了低温烧结Bi取代钇铁石榴石的电性质.采用固相反应制备多晶钇铁石榴石陶瓷Y2BiFe5O12(YIG∶Bi)和Y3Fe5O12(YIG).采用X射线衍射衍射(XRD)表征粉末及陶瓷样品的相组成,结果表明,Bi取代可以显著降低钇铁石榴石的成相温度和烧结温度.复阻抗谱分析表明,YIG∶Bi样品的复阻抗谱表现为两个Cole-Cole半圆,其低频半圆和高频半圆分别对应高直流电阻的晶界和低直流电阻的晶粒的电响应,物理结构可以用由串联的两个RC回路组成的等效电路来表示;而YIG样品的复阻抗谱只有一个对应为晶界电响应的半圆,其等效电路为一个RC回路.电阻随温度的变化表明,材料的导电机制符合Arrhenius规律,为半导体型的热激活过程.

The effects of Bi-substitution on the complex impedance spectral of yttrium iron garnet (YIG) were studied in this paper.The polycrystalline yttrium iron garnet Ys_2BiFe_5O_ 12 (YIG∶Bi) and Y_3Fe_5O_ 12 (YIG) samples were prepared by solid-reaction method.The complex impedance spectra wer measured in the frequency range from 1kHz to 100MHz at several temperatures between 210℃ and 500℃.The complex impedance sample shows that the YIG∶Bi can be represented by double Cole-Cole semicircles,and the YIG can be rep...