La_(1-x)Sr_xCoO_3体系的绝缘体-金属相变  

Metal-Insulator transition of La_(1-x)Sr_xCoO_3 system

作　　者：蒋丽珍[1] 何雪竹[2] 余虹[3] 邬良能[1] 

机构地区：[1]中国计量学院理学院,浙江杭州310018 [2]杭州市陈经伦体育学校,浙江杭州310007 [3]杭州师范学院基础教育学院,浙江杭州310036

出　　处：《中国计量学院学报》2006年第3期224-227,共4页Journal of China Jiliang University

基　　金：国家自然科学基金资助项目(No.10225417;10575092)

摘　　要：通过粉末X射线衍射分析确定了钙钛矿氧化物La1-xSrxCoO3（0.1≤x≤0.5）体系的结构,由Rietveld方法拟合得到晶格参数随Sr掺杂量的变化.在80～300 K温度范围的直流电阻率测量表明,材料的电性质在x=0.2和x=0.3之间展示了从半导体到金属的相变.x=0.2样品已接近绝缘体-金属（I-M）相变的边缘.研究结果表明,La1-xSrxCoO3（0.1≤x≤0.5）体系的I-M相变不仅依赖于Sr浓度x,也依赖于样品的制备技术.The crystal structure of perovskite oxide La1-xSrxCoO3（0≤x≤0.5） was determined by powder X-ray diffraction. Lattice parameters as a function of Sr-concentration x were obtained by using Rietveld method. The dc resistivity investigated in the temperature range of 80-300 K indicates that the electric properties exhibit a metal-insulator （semiconducting） （I-M） transition for 0.2〈x〈0. 3. The sample with x= 0. 2 is close to the M--I transition boundary. Our result shows that Metal-Insulator transition of La1-xSrxCoO3 system not only depends on Sr content x, but also on the preparation techniques.

关 键 词：钙钛矿 晶格参数 电阻率 

分 类 号：O482.4[理学—固体物理]