作　　者： ; ;

机构地区： 天津大学理学院物理系

出　　处： 《低温物理学报》 2000年第6期443-448,共6页

摘　　要： 实验研究了由Pechini方法制备的La1-xNaxMnOz 系列多晶陶瓷样品的磁性质、热性质和输运性质 ,在 77K到居里温度范围得到了较高的低场磁电阻 ,并且 ,在电阻率 温度曲线观察到了两个峰 :一个在居里温度附近 ,另外一个在远低于居里温度处 .退火实验表明 ,氧含量的不均匀是造成电阻率 温度曲线上存在两个峰的主要原因 . Polycrystalline La\-\{1- x \}Na\- x MnO\- z ceramics were prepared by Pechini process and the magnetic and transport properties have been investigated. Low field magnetoresistance in temperature range from 77K to Curie temperature was obtained. Additionally, two obvious peaks were observed in the resistivity versus temperature curve. Differential Scanning Calorimetry results and our calculation show that a second order phase transition occurs at Curie temperature. Postannealing experiment results indicate that the resistivity peak below Curie temperature originates from oxygen inhomogeneous of the as prepared samples.

关 键 词： 钙钛矿型锰氧化物 结构 热性质 电磁性质 低温物性

领　　域： [理学] [理学]