钙钛矿结构La_(1-x)Sr_xCoO_3(x=0.7,0.8,0.9,1.0)样品的铁磁相变和绝缘-金属转变  

STUDY OF ELECTRICAL AND MAGNETIC PROPERTIES OF POLYCRYSTAL La_(1-x)Sr_xCoO_3-δ (0.7≤x≤1)

作　　者：周新[1] 马玉彬[1] 连贵君[1] 熊光成[1] 

机构地区：[1]北京大学物理学院,北京100871

出　　处：《低温物理学报》2006年第1期1-5,共5页Low Temperature Physical Letters

基　　金：国家科技部重点基础研究发展规划项目(项目编号:G20000036505)资助的课题~~

摘　　要：利用固相反应法及溶胶凝胶法我们制备了多晶La1-xSrxCoO3(x=0.7,0.8,0.9,1.0)样品.X射线衍射谱表明,La1-xSrxCoO3样品呈ABO3型钙钛矿结构,晶格常数随着x的增加而增大.与钙钛矿结构的锰氧化物类似,电阻率随温度变化以及磁化强度随温度变化的关系强烈依赖于掺杂浓度.x=0.7和0.8的样品在低温下显示铁磁性,而x=0.9和1.0的样品磁化强度随温度变化没有显示铁磁转变.电阻率随温度的变化似乎与磁化率测量相对应,在x=0.8和0.9样品之间存在绝缘-金属转变.Perovskites La1-xSrxCoO3（x = 0.7, 0.8, 0.9 and 1 ） samples were synthesized by sol-gel and solid state reaction methods. Structures were characterized and lattice constants were obtained by X-ray diffraction pattern. The temperature dependence of electrical resistivity, the ferromagnetic-paramagnetic transition temperature （Tc） and magnetization under the same magnetic field depend strongly on Co^3＋/ Co^4＋ ratio, which can be explained by double-exchange interaction.

关 键 词：La1-xSrxCoOe 钙钛矿结构 双交换模型 

分 类 号：O469[理学—凝聚态物理]