Heusler合金Mn50–xCrxNi42Sn8的相变、磁性与交换偏置效应  

Phase transformation, magnetic properties, and exchange bias of Heusler alloy Mn50–xCrxNi42Sn8

作　　者：Algethami Obaidallah A 李歌天[1] 柳祝红[1] 马星桥[1] Algethami Obaidallah A;Li Ge-Tian;Liu Zhu-Hong;Ma Xing-Qiao(Department of Physics,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学物理系

出　　处：《物理学报》2020年第5期244-250,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51671024)资助的课题~~

摘　　要：研究了Mn50–xCrxNi42Sn8 (x=0, 0.4, 0.6, 0.8)多晶样品的相变、磁性和交换偏置效应.结果表明,该系列合金在室温下都具有非调制的四方马氏体结构.马氏体逆相变温度随Cr含量增加而逐渐降低. 20 k Oe磁场下的M-T曲线表明,该系列合金的磁性比较弱.两相之间的磁性差最大为△M=7.61 emu/g.磁性的变化主要与Mn-Mn间距的变化以及Ni(A位)-Mn(D位)间杂化作用的强弱有关.在低温下,马氏体相的磁性随着Cr含量增加而增强.在500 Oe的外加磁场作用下,从室温冷却到5 K,在Mn50Ni42Sn8合金中观察到高达2624 Oe的交换偏置场.随着Cr含量的增加,交换偏置场逐渐减小.当Cr含量x=0.8时,随着冷却场的增加, 5 K时的交换偏置场先迅速增加然后逐渐减小.当冷却场为500 Oe时,交换偏置场最大.这主要归因于自旋玻璃态与反铁磁性区域的界面交换耦合作用的变化.In this paper, phase transformations, magnetic properties and exchange bias of Mn50–xCrxNi42Sn8(x = 0,0.4, 0.6, 0.8) polycrystalline samples are investigated. It is found that each of all the alloys has a tetragonal martensite structure at room temperature. The transformation temperature decreases with the increase of Cr content. The maximum magnetization difference between martensite and austenite phase is △M = 7.61 emu/g.The change of magnetic properties is mainly related to the change of Mn-Mn distance and the hybridization strength between Ni(A)-Mn(D). The ferromagnetism of martensite can be enhanced by Cr doping. The exchange bias field is observed to reach up to as high as 2624 Oe in Mn50Ni42Sn8 alloy after cooling from room temperature to 5 K in 500 Oe magnetic field, which decreases gradually with the increase of Cr content.Furthermore, the exchange bias field increases first and then followed by a decrease with the increase of the cooling field in Mn49.2Cr0.8Ni42Sn8. This is mainly attributed to the change of the interface exchange coupling between the spin glass state and antiferromagnetic region.

关 键 词：马氏体相变 交换偏置效应 HEUSLER合金 

分 类 号：TG132[一般工业技术—材料科学与工程]