相分离Gd_5Ge_4合金温度依赖的多重磁转变行为研究  

DEPENDENCE OF MAGNETIC BEHAVIOR ON TEMPERATURE IN PHASE SEPARATED Gd_5Ge_4 ALLOY

作　　者：陈镇平[1] 石开[1] 张晓勇[2] 苏玉玲[1] 薛运才[1] 王春梅[1] 张金仓[2] 

机构地区：[1]郑州轻工业学院技术物理系,郑州450002 [2]上海大学物理系,上海200444

出　　处：《低温物理学报》2010年第4期252-256,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金(项目编号:10875107;10774097);河南省自然科学基金(项目编号:082300440080);河南省教育厅自然科学基础研究计划项目(项目编号:2008A140014)资助的课题

摘　　要：系统研究了Gd5Ge4合金的结构和磁特性的温度依赖关系,结果表明,实验样品Gd5Ge4室温下具有典型的pnma空间群正交结构,通过测量该合金场冷(FC)和零场冷(ZFC)下的热磁曲线以及交流磁化率随温度变化曲线,结合不同温度下的磁滞回线(M～H),观察到当外加磁场为1T时,体系在几个特征温度T1=10K、T2=26K、T3=127K和T4=235K附近磁化强度出现了异常变化,反映在这些特征温度下的体系出现了复杂的多重磁转变行为,初步分析了在各特征温度附近发生的磁相变的属性,探讨了相分离中铁磁成分与温度的关联,其结果对扩展包括强关联锰氧化物在内的相分离体系物理机理的理解具有一定的参考价值和借鉴意义。The structure and the dependence of magnetic properties on temperature in Gd5Ge4 Alloy were systematically studies.X-ray diffractions indicate that Gd5Ge4 has an orthorhombic type structure withpnmaspace group at room temperature.Considering all the results of the M～Tcurves at field-cooled（FC）and zero-filed-cooled（ZFC）and the curve AC magnetic susceptibility to temperature and hysteresis loop at ZFC,the unusual changes of magnetization had been found at several characteristic temperature（T1=10K,T2=26K,T3=127K,T4=235K）on the 1Texternal field.This indicated that there existed mulriple magnetic behavior around these characteristic temperatures in Gd5Ge4 Alloy.The attributes of magnetic phase transition around the different characteristic temperature were primary analyzed and the relationship of the ferromagnetism（FM）proportion and the temperature were disused.The experimental results have reference values for understanding the physical mechanism of phase separated systems including the strong correlation manganese oxide.

关 键 词：Gd5Ge4合金 磁相变 相分离 磁热效应 

分 类 号：O482.5[理学—固体物理]