层状钙钛矿La_(1.2)Sr_(1.8)Cu_(0.04)Mn_(1.96)O_7中的自旋玻璃态和输运性质  

Spin-Glass State and Transport Property of Layered Perovskite La_(1.2)Sr_(1.8)Cu_(0.04)Mn_(1.96)O_7

作　　者：司继伟[1] 曹庆琪[1] 顾本喜[1] 都有为[1] 

机构地区：[1]南京大学固体微结构国家实验室,江苏南京210093

出　　处：《中国稀土学报》2005年第6期723-726,共4页Journal of the Chinese Society of Rare Earths

基　　金：国家重点基础研究项目(G1999064508)资助课题

摘　　要：用固相烧结的方法成功制备了层状钙钛矿锰氧化物La1.2Sr1.8Cu0.04Mn1.96O7多晶样品。研究发现,在层状钙钛矿La1.2Sr1.8Mn2O7中,用Cu替代Mn对其磁、电的性质影响非常显著。随温度的降低样品表现出从顺磁(PM)到铁磁(FM)及自旋玻璃态(SG)等复杂的磁相变行为。电性测量表明,在整个观察的温区内都表现出绝缘体或半导体的性质。对电阻率-温度曲线进行拟合表明:在低温区采用变程跳跃模型和在高温区采用小极化子模型都得到了较好的线性关系。Polycrystallite of layered perovskite La1.2Sr1.8Cu0.04Mn1.96O7 was synthesized by solid state reaction method. The result shows that the effect of Cu substitute for Mn on the magnetic and electrical properties of La1.2Sr1.8Mn1.96O7 is very obvious. With the temperature decreasing, the system undergoes a transition from paramagnetic （PM） to ferromagnetic （FM） and further to spin-glass （SG）. Temperature dependence of resistivity indicates that the sample is insulator or semiconductor in the whole observed temperature range. Resistivity curve is fitted well by vary range hopping （VRH） model at low temperature and small polaron hopping（SPH） model at high temperature.

关 键 词：层状钙钛矿 自旋玻璃 磁电阻 变程跳跃 小极化子 稀土 

分 类 号：TM273[一般工业技术—材料科学与工程]