Magnetocaloric and critical behavior in the austenitic phase of Gd-doped Ni50Mn37Sn13 Heusler alloys
Magnetocaloric and critical behavior in the austenitic phase of Gd-doped Ni50Mn37Sn13 Heusler alloys
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DOI：
10.1016/j.jallcom.2013.12.072
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发表时间：
2014-12
影响因子：
6.2
通讯作者：
P. Zhang;T. Phan;N. H. Dan;T. Thanh;Seong-cho Yu
中科院分区：
文献类型：
--
作者：
P. Zhang;T. Phan;N. H. Dan;T. Thanh;Seong-cho Yu
研究了电弧熔炼法制备的Ni 50− yGdyMn 37 Sn 13（y= 1和3）合金的磁相变行为。马氏体相被发现强烈抑制少量的Gd掺杂。基于奥氏体相居里温度附近的等温磁化曲线，通过Kouvel-Fisher方法仔细确定了两种合金在奥氏体相中的临界行为。当y= 1时，临界指数分别为β= 0.473±0.020和γ= 1.141±0.017（T C A= 299.0± 0.2K）;当y= 3时，临界指数分别为β= 0.469±0.068和γ= 1.214±0.042（T C A= 302.9± 0.7K）。两种合金A相铁磁相变的临界指数基本符合平均场模型（β= 0.5，γ= 1），但略有偏差，表明铁磁相互作用具有长程有序性。这种临界行为可以归因于Gd掺杂引起的原子无序引起的磁不均匀性。
The magnetic phase transition behavior were investigated in detail in Ni 50− y Gd y Mn 37 Sn 13 (y= 1 and 3) alloys prepared by arc-melting method. The martensite phase was found to be strongly suppressed by a small amount of Gd doping. Based on isothermal magnetization curves around Curie temperature of the austenite (T C A) phase, critical behavior in the austenite phases of both alloys were determined carefully by the Kouvel–Fisher method. The critical exponents were found to be β= 0.473±0.020 and γ= 1.141±0.017 with T C A= 299.0±0.2 K for y= 1, and β= 0.469±0.068 and γ= 1.214±0.042 with T C A= 302.9±0.7 K for y= 3, respectively. The values of the critical exponents for the ferromagnetic phase transition in the A phase of two alloys can be basically ascribed in the mean-field model (with β= 0.5, γ= 1) with slightly deviation, revealing a long-range order of ferromagnetic interactions. Such critical behavior can be attributed to the magnetic inhomogeneities originated from the atomic disorder introduced by Gd doping.