哈斯勒合金Ni-Mn-Sn的马氏体相变与反磁热性质

通过结构以及磁性测量，研究了哈斯勒合金Ni₅₀Mn_25+xSn_25-x (x=11,12)的马氏体相变和磁热性质.结果表明，与样品在奥氏体相的磁性不同，由于在马氏体相中反铁磁交换作用的增强，导致铁磁和反铁磁在马氏体状态下共存.此外，通过Maxwell方程，研究了两样品在不同磁场变化下马氏体相变温度附近的反磁热性质，并阐明了该系列合金产生大的正磁熵变(ΔS_M)不仅与其在降温过程中发生马氏体相变所导致的磁跃变(ΔM)有关，而且与发生马氏体相变所经历的温度区间有密切的联系. 关键词： 哈斯勒合金 Ni-Mn-Sn 马氏体相变 正磁熵变

Investigation of martensitic transition and inverse magnetocaloric property in Ni-Mn-Sn Heusler alloys

The martensitic transition and magnetocaloric property in Ni₅₀Mn_25+xSn_25-x (x=11, 12) Heusler alloys were investigated by means of structure and magnetism measurements. The results show that the antiferromagnetic interaction strengthens in the martensitic state, leading to the coexistence of ferromagnetic and antiferromagnetic interaction in this state, which is different from the magnetic property of austenitic state in these alloys. Furthermore, based on Maxwell equation, the inverse magnetocaloric property near martensitic transition temperature of this system was studied. It was found that large positive magnetic entropy change (ΔS_M) depends on both magnetic jumping (ΔM) and temperature region during martensitic transition.