Giant magnetic entropy change in manganese perovskite La0.67Sr0.16Ca0.17MnO3 near room temperature
Giant magnetic entropy change in manganese perovskite La0.67Sr0.16Ca0.17MnO3 near room temperature
复制标题
DOI：
10.1016/j.jallcom.2014.06.169
复制
发表时间：
2014-12
影响因子：
6.2
通讯作者：
Za. Mohamed;E. Tka;J. Dhahri;E. Hlil
中科院分区：
文献类型：
--
作者：
Za. Mohamed;E. Tka;J. Dhahri;E. Hlil
研究了La 0.67Sr0.16Ca0.17MnO3钙钛矿的结构、磁性和磁热性能.在制备阶段使用固相反应方法。用Rietveld方法对样品进行了X射线衍射分析，结果表明，样品属于畸变菱面体体系，空间群为R3 ~（？）c。在0.05T的外加磁场下，磁化强度（M）随温度（T）的变化表明，在居里温度（TC = 336 K）附近发生了从铁磁（FM）到顺磁（PM）的转变。使用Arrott图，发现该转变是二阶的。等温磁化测量允许我们通过热力学麦克斯韦关系来确定磁熵变（ΔS M）。从等温磁化曲线上可以看出，在我们的样品中观察到一个大的Δ SM，其峰值集中在各自的TC附近。磁场变化为5 T时，磁熵变Δ S M max的最大值在335 K时为5.51 J kg− 1 K− 1。此外，该化合物显示出约234 J/kg的大的相对冷却功率（RCP）值，而在5 T的应用领域中获得了174 J/kg的最大制冷量。因此，所研究的样品可以被认为是一种潜在的磁制冷材料。
Structural, magnetic and magnetocaloric properties of La 0.67 Sr 0.16 Ca 0.17 MnO 3 perovskite have been studied. A solid state reaction method was used in the preparation phase. X-ray diffraction analysis using Rietveld refinement revealed that this sample crystallizes in the distorted rhombohedral system with R 3‾ c space group. The variation of magnetization (M) vs. temperature (T), under an applied magnetic field of 0.05T, revealed a transition from a ferromagnetic (FM) to paramagnetic (PM) phase at around Curie temperature (T C= 336 K). Using Arrott plots, it was found that the transition is of a second-order. Isothermal measurements of magnetization allow us, through thermodynamic Maxwell relations, to determine the magnetic entropy change (ΔS M). A large ΔS M deduced from isothermal magnetization curves, has been observed in our sample with a peak centered around its respective T C. The maximum of the magnetic entropy change Δ S M max in a magnetic field change of 5T is found to be 5.51 J kg− 1 K− 1 at 335 K. In addition, the compound showed a large relative cooling power (RCP) value of about 234 J/kg while the maximum refrigerant capacity of 174 J/kg was attained at the applied field of 5T. As a result, the studied sample can be considered as a potential material for magnetic refrigeration.