钙钛矿锰氧化物La0.775Eu0.025Sr0.2MnO3的磁性和磁卡效应  

Magnetic and Magnetocaloric Effect of Perovskite Manganese Oxide La0.775Eu0.025Sr0.2MnO3

作　　者：陈红伟 曹凤泽 尚佳彬[2] 李国峰[2] 鲁毅[1] 赵建军[1] 金香[1] Chen Hongwei;Cao Fengze;Shang Jiabin;Li Guofeng;Lu Yi;Zhao Jianjun;Jin Xiang(Key Laboratory of Magnetism and Magnetic Materials at Universities of Inner Mongolia Autonomous Region,Baotou Teachers' College, Baotou 014030, China;Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology,College of Electrical Information and Optical Engineering, Nankai University, Tianjin 300350, China)

机构地区：[1]包头师范学院物理科学与技术学院,内蒙古自治区高等学校磁学与磁性材料重点实验室,内蒙古包头014030 [2]南开大学电子信息与光学工程学院天津市光电传感器与传感网络技术重点实验室,天津300350

出　　处：《南开大学学报（自然科学版）》2019年第4期51-56,共6页Acta Scientiarum Naturalium Universitatis Nankaiensis

基　　金：国家自然科学基金(11164019,51562032,61565013);内蒙古自然科学基金(2015MS0101,2015MS0109);内蒙古高校科研重点项目基金(NJZZ11166,NJZY16237,NJZY12202);包头市科技局项目(2015Z2011);包头师范学院青年科学研究基金(BSYKJ2014-22)

摘　　要：采用传统的固相反应法制备了多晶样品La0.775Eu0.025Sr0.2MnO3,通过测量样品的XRD谱线、磁化强度随温度的变化曲线(M-T)、等温磁化曲线(M-H),重点研究了样品的的磁性和磁卡效应.研究发现:样品的晶体结构为立方钙钛矿结构,其空间群为Pbnm.该样品在15-340 K温区内表现为铁磁特征,340-364 K温区内表现出类Griffiths相特征,364-400 K温区内表现出顺磁特征.临界行为分析表明该样品与平均场模型拟合较好.样品在居里温度Tc=290 K附近,系统发生二级相变,在7 T外场下,样品的最大等温磁熵变值为2.60 J/(kg·K),磁制冷功率为439.40 J/kg,因此,该材料具有室温下实现磁制冷的潜能.The polycrystalline sample La0.775Eu0.025Sr0.2MnO3 was prepared by the traditional solid phase reaction method.The XRD line and magnetization intensity as a function of temperature(M-T)and isothermal magnetization curve(M-H)were measured.The magnetic and magnetocaloric effects of the sample was mainly studied.The crystal structure of the sample is cubic perovskite structure,and its space group is Pbnm.The sample exhibited ferromagnetic characteristics in the 15-340 K temperature region,the Griffiths phase in the 340-364 K temperature region,and the paramagnetic characteristics in the 364-400 K temperature region.The critical behavior analysis shows that the sample fits well with the main field model.The sample has a secondary phase transition and a maximum magnetic entropy change in the vicinity of the Curie temperature TC=290 K.Under the external field of 7 T,the maximum magnetic entropy change of the sample is 2.60 J/(kg·K),and the magnetic refrigeration efficiency is 439.40 J/kg,therefore,the material has the potential to achieve magnetic refrigeration at room temperature.

关 键 词：磁性 磁熵变 磁制冷 临界行为 

分 类 号：O469[理学—凝聚态物理]