Dhahri Ah, Dhahri E, Hlil E K
Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, Université de Sfax BP 1171 3000 Tunisia
Faculté des Sciences de Monastir Avenue de l'environnement 5019 Monastir Tunisia.
RSC Adv. 2019 Feb 13;9(10):5530-5539. doi: 10.1039/c8ra09802f. eCollection 2019 Feb 11.
La Bi BaMnO ( = 0 and 0.05) ceramics were prepared the sol-gel method. Structural, magnetic and magnetocaloric effects have been systematically studied. X-ray diffraction shows that all the compounds crystallize in the rhombohedral structure with the 3̄ space group. By analyzing the field and temperature dependence of magnetization, it is observed that both samples undergo a second order magnetic phase transition near . The value of decreases from 340 K to 306 K when increasing from 0.00 to 0.05, respectively. The reported magnetic entropy change for both samples was considerably remarkable and equal to 5.8 J kg K for = 0.00 and 7.3 J kg K for = 0.05, respectively, for = 5 T, confirming that these materials are promising candidates for magnetic refrigeration applications. The mean-field theory was used to study the magnetocaloric effect within the thermodynamics of the model. Satisfactory agreement between experimental data and the mean-field theory has been found.
采用溶胶-凝胶法制备了LaBiBaMnO（=0和0.05）陶瓷。对其结构、磁性和磁热效应进行了系统研究。X射线衍射表明，所有化合物均以3̄空间群的菱面体结构结晶。通过分析磁化强度与磁场和温度的关系，观察到两个样品在附近都经历了二级磁相变。当从0.00增加到0.05时，的值分别从340 K降低到306 K。对于两个样品，报道的磁熵变相当显著，对于=0.00，在=5 T时磁熵变为5.8 J kg K，对于=0.05，磁熵变为7.3 J kg K，这证实了这些材料是磁制冷应用的有前途的候选材料。利用平均场理论在模型的热力学范围内研究磁热效应。实验数据与平均场理论之间取得了令人满意的一致性。
