Dhahri M, Dhahri J, Hlil E K
Laboratoire de la matière condensée et des nanosciences, Univercité de Monastir 5019 Tunisia
Institut Neel, CNRS et Univercité Joseph Fourrier B. P. 166 38042 Grenoble France.
RSC Adv. 2018 Jan 31;8(10):5395-5406. doi: 10.1039/c7ra12905j. eCollection 2018 Jan 29.
A detailed study of the structural, magnetic, magnetocaloric and electrical effect properties in polycrystalline manganite LaSmSrMnInO is presented. The X-ray diffraction pattern is consistent with a rhombohedral structure with 3̄ space group. Experimental results revealed that our compound prepared a sol-gel method exhibits a continuous (second-order) ferromagnetic (FM) to paramagnetic (PM) phase transition around the Curie temperature ( = 300 K). In addition, the magnetic entropy change was found to reach 5.25 J kg K under an applied magnetic field of 5 T, corresponding to a relative cooling power (RCP) of 236 J kg. We have fitted the experimental data of resistivity using a typical numerical method (Gauss function). The simulation values such as maximum resistivity ( ) and metal-semiconductor transition temperature ( ), calculated from this function, showed a perfect agreement with the experimental data. The shifts of these parameters as a function of magnetic field for our sample have been interpreted. The obtained values of and , determined by analyzing the Arrott plots, are found to be = 298.66 ± 0.64 K, = 0.325 ± 0.001 and = 1.25 ± 0.01. The critical isotherm ( , ) gives = 4.81 ± 0.01. These critical exponent values are found to be consistent and comparable to those predicted by the three-dimensional Ising model with short-range interaction. Thus, the Widom scaling law is fulfilled.
本文对多晶锰酸盐LaSmSrMnInO的结构、磁性、磁热效应和电效应特性进行了详细研究。X射线衍射图谱与具有3̄空间群的菱面体结构一致。实验结果表明，我们采用溶胶-凝胶法制备的化合物在居里温度（ = 300 K）附近呈现连续（二级）铁磁（FM）到顺磁（PM）的相变。此外，发现在5 T的外加磁场下，磁熵变达到5.25 J kg K，对应相对制冷功率（RCP）为236 J kg。我们使用典型的数值方法（高斯函数）拟合了电阻率的实验数据。从该函数计算得到的诸如最大电阻率（ ）和金属-半导体转变温度（ ）等模拟值与实验数据显示出完美的一致性。我们对样品的这些参数随磁场的变化进行了解释。通过分析阿罗特图确定的 和 的值分别为 = 298.66 ± 0.64 K， = 0.325 ± 0.001和 = 1.25 ± 0.01。临界等温线 （ ， ）给出 = 4.81 ± 0.01。发现这些临界指数值与具有短程相互作用的三维伊辛模型预测的值一致且可比。因此，维杜姆标度律得到满足。
