(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)
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。
关键字: (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
（1. School of Materials Science and Engineering, Nanchang University,Nanchang 330031, China;2. School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;3. State Key Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China）
Abstract:A series of polycrystal 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 Tc, which is a little smaller than that of La2/3Ca1/3MnO3 sample. The maximum value of magnetic entropy change for Y3+ 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.
Key words: (La(1−x−y)Yy)2/3Ca1/3MnO3 compounds; solid-state reaction; magnetocaloric effect; magnetic entropy change; vacancy doping
