Bouzidi Souhir, Gdaiem Mohamed Amara, Dhahri J, Hlil E K
Laboratoire de la Matière Condensée et des Nanosciences, Département de Physique, Faculté des Sciences de Monastir Avenue de l'Environnement Monastir- 5019 Tunisia
Institut Néel, CNRS et Université Joseph Fourier BP 166 F-38042 Grenoble Cedex 9 France.
RSC Adv. 2018 Dec 20;9(1):65-76. doi: 10.1039/c8ra09166h. eCollection 2018 Dec 19.
In this paper, LaCa Na MnO ( = 0.15 and 0.20) samples were prepared by the flux method. Crystallographic study revealed that the = 0.15 sample is characterized by the coexistence of a mixture of orthorhombic and rhombohedral structures with and 3̄ space groups, respectively. While, the = 0.20 sample crystallized in the rhombohedral structure with a 3̄ space group. Magnetic data, under a magnetic field of 0.05 T, indicated that our samples undergo a ferromagnetic (FM)-paramagnetic (PM) phase transition, on increasing the temperature. The magnetic field dependence of the magnetocaloric properties of LaCa Na MnO ( = 0.15 and 0.20) samples, with the second phase transition, was investigated. Near room temperature, the = 0.20 sample exhibited a large magnetic entropy change with maxima of 6.01 and 3.12 J kg K, respectively, under applied magnetic fields of 5 and 2 T. Also, the relative cooling power (RCP) was calculated. According to hysteresis cycles, for our studied samples, at 10 K a typical soft FM behavior with a low coercive field was observed. These results make our samples promising candidates for magnetic refrigerators, magnetic recording, and memory devices.
在本文中，采用助熔剂法制备了LaCaNaMnO（= 0.15和0.20）样品。晶体学研究表明，= 0.15的样品分别以正交晶系和菱面体结构的混合物共存为特征，其空间群分别为和3̄。而= 0.20的样品以具有3̄空间群的菱面体结构结晶。在0.05 T的磁场下，磁性数据表明，随着温度升高，我们的样品经历了铁磁（FM）-顺磁（PM）相变。研究了具有二级相变的LaCaNaMnO（= 0.15和0.20）样品磁热性能的磁场依赖性。在室温附近，= 0.20的样品在5 T和2 T的外加磁场下分别表现出6.01和3.12 J kg K的最大磁熵变化。此外，还计算了相对制冷量（RCP）。根据磁滞回线，对于我们研究的样品，在10 K时观察到具有低矫顽场的典型软铁磁行为。这些结果使我们的样品有望成为磁制冷机、磁记录和存储设备的候选材料。
