中文摘要：

研究了Y0．75Ca0．25MnO3体系的结构和电磁特性，结果表明，场冷（FC）和零场冷（ZFC）直流磁化曲线在低温下存在典型的分叉现象，相应的Tcusp=34K；不同频率下交流磁化测量表明了随着频率的增加自旋冻结温度Tf=Tcusp向高温区移动，结合电输运测量，证明Y0．75Ca0．25MnO3体系为一典型的自旋玻璃绝缘（SGI）体系。

英文摘要：

The structure and electromagnetic properties of perovskite manganite Y0.75 Ca0.25 MnO3 were systematically investigated. In low temperatures, a typical behavior of bifurcation was observed between field-cooled （FC） and zero-field-cooled （ZFC） magnetization with a cusp at Tcusp =34K in the ZFC magnetization curve. AC susceptibility also showed a cusp at Tf= Tcusp, called spin-glass freezing temperature, which shifts to high temperature with increasing frequencies. With the resistivity behavior in the electrical transport measurement, we considered an intrinsic spin-glass insulator （SGI） in the Y0.75 Ca0.25 MnO3 system.