Particle size effects on La0.7Ca0.3MnO3: size-induced changes of magnetic phase transition order and magnetocaloric study
Particle size effects on La0.7Ca0.3MnO3: size-induced changes of magnetic phase transition order and magnetocaloric study
复制标题
粒度对 La0.7Ca0.3MnO3 的影响：尺寸引起的磁相变顺序变化和磁热研究
DOI：
10.1016/j.jmmm.2010.02.038
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发表时间：
2010-08-01
影响因子：
2.7
通讯作者：
Sun, Yuping
中科院分区：
文献类型：
--
作者：
Tang, Wei;Lu, Wenjian;Sun, Yuping
研究了不同粒径La0.7Ca0.3MnO3陶瓷的结构、磁性能和磁热效应。研究发现，随着粒径的减小，居里温度先升高后降低，磁相变类型由一阶转变为二阶，这可能与表面压力效应有关。最大磁熵变δ S-M（max）和相对冷却功率（RCP）随粒径的减小呈非单调行为。而对于3400 nm样品，在2.0和4.5 T的磁场变化下，磁熵变化δ S-M分别达到最大值6.41和8.63 J/kg K。此外，La0.7Ca0.3MnO3在较低磁场下的估计大RCP值与相应温度范围内典型磁性制冷剂材料的RCP值相当，表明这些化合物可能是磁制冷的有希望的候选者。(C) 2010 Elsevier B.V.版权所有
The structure, magnetic properties, and magnetocaloric effect of La0.7Ca0.3MnO3 ceramics with different particle sizes have been investigated. It is found that the Curie temperature increases first, and then decreases as particle size decreases and the type of magnetic phase transition changes from first-order to second-order, which may be attributed to surface pressure effects. The maximum magnetic entropy change -Delta S-M(max) and relative cooling power (RCP) show non-monotonic behaviors with decreasing the particle size. However, for the 3400 nm sample, the magnetic entropy change -Delta S-M reaches the maximum values of 6.41 and 8.63 J/kg K for the field changes of 2.0 and 4.5 T, respectively. Furthermore, the estimated large RCP values under lower magnetic fields in La0.7Ca0.3MnO3 are comparable with those of typical magnetic refrigerant materials in the corresponding temperature range, suggesting those compounds might be promising candidates for magnetic refrigeration. (C) 2010 Elsevier B.V. All rights reserved.