稀土空位锰氧化物(La_((1-x-y))Y_y)_(2/3)Ca_(1/3)MnO_3的磁热效应  

Magnetocaloric effect on (La_((1-x-y))Y_y)_(2/3)Ca_(1/3)MnO_3 manganese oxides system with rare-earth vacancies

作　　者：罗广圣[1] 李小怡[1] 周正有[1] 刘光华[1] 熊惟皓[2] 吴小山[3] 

机构地区：[1]南昌大学材料科学与工程学院,南昌330031 [2]华中科技大学材料科学与工程学院,武汉430074 [3]南京大学固体微结构国家重点实验室,南京210093

出　　处：《中国有色金属学报》2007年第12期2005-2009,共5页The Chinese Journal of Nonferrous Metals

基　　金：江西省自然科学基金资助项目(0150014)

摘　　要：采用固相反应法制备La(1-x)2/3Ca1/3MnO3(x=0.0,0.04)和(La0.7Y0.3)2/3Ca1/3MnO3系列样品,测量不同温度下的磁化强度—磁场曲线,计算样品的磁熵变,研究La空位掺杂和Y3+离子掺杂对磁热效应的影响。结果表明,La空位掺杂(x=0.04)的样品在居里温度附近磁熵变最大值为6.22 J/(kg.K),这比La2/3Ca1/3MnO3磁熵变最大值(6.26 J/(kg.K))稍有降低;而Y3+离子掺杂的样品在温度60 K时和磁场强度2 T下,其磁熵变最大值为0.568 J/(kg.K),并且磁熵变随温度变化有继续增大的趋势。这表明(La0.7Y0.3)2/3Ca1/3MnO3可以作为一定温区的磁致冷材料。A series ofpolycrystal samples of La（1-x）2/3Ca1/3MnO3（x=0.0, 0.04） and （La0.7Y0.3）2/3Ca1/3MnO3 were prepared by standard solid-state reaction method. The curves of magnetic-field dependence on magnetization were measured at various temperatures and the entropy changes of the samples were calculated. The influences of La vacancy doping and y3＋ doping on magnetocaloric effect were investigated. The results show that the maximum value of magnetic entropy change for La vacancy doping sample （x=0.04） is 6.22 J/（kg·K） near Curie temperature To, which is a little smaller than that of La2/3Ca1/3MnO3 sample. The maximum value of magnetic entropy change for Y^3＋ doping sample is 0.568 J/（kg·K） at temperature of 60 K and in magnetic field of 2 T, and the magnetic entropy change increases with the increase of temperature, which indicates that the perovskite manganites are suitable candidates as working substances in magnetic refrigeration technology.

关 键 词：(La(1-x-y)Yy)2/3Ca1/3MnO3化合物 固相反应 磁热效应 磁熵变 空位掺杂 

分 类 号：TH117.1[机械工程—机械设计及理论]