Combined effect of magnetic field and hydrostatic pressure on the phase transitions exhibited by Ni-Mn-In metamagnetic shape memory alloy
Combined effect of magnetic field and hydrostatic pressure on the phase transitions exhibited by Ni-Mn-In metamagnetic shape memory alloy
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DOI：
10.1016/j.actamat.2020.04.008
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发表时间：
2020-07
期刊：
影响因子：
9.4
通讯作者：
P. Lázpita;V. L'vov;J. R. Fernández;J. Barandiaran;V. Chernenko
中科院分区：
文献类型：
--
作者：
P. Lázpita;V. L'vov;J. R. Fernández;J. Barandiaran;V. Chernenko
我们对原型变磁形状记忆合金 Ni50Mn34.5In15.5 在静水压力以及压力和磁场联合作用下的磁结构和磁转变进行了系统研究。压力扩大了反铁磁马氏体相的稳定区域。在低磁场下，奥氏体（TCA）和马氏体（TCM）居里温度的压力导数表现出相反的符号。这一事实在朗道热力学模型的框架中被描述为由马氏体的弱长程反铁磁状态引起的。利用TCA和TCM的压力导数的实验值估计了两个体积磁弹性常数。建立了 TCA 和 TCM 压力变化符号与 Mn-Mn 最近邻之间的距离之间的相关性，该相关性与经验 Castelliz-Kanomata 图相匹配。当马氏体相变 (MT) 温度 TM 在压力影响下接近 TCA 时，马氏体相变 (MT) 的熵变 ΔSMT 增大，但在恒定非零压力下，这种依赖性是相反的。
We present a systematic study of the magnetostructural and magnetic transitions in the prototype metamagnetic shape memory alloy Ni50Mn34.5In15.5under hydrostatic pressure and combined pressure and magnetic field. Pressure extends the area of stability of the antiferromagnetic martensitic phase. At low magnetic field the pressure derivatives of the Curie temperatures of austenite,TCA, and martensite,TCM, show opposite signs. This fact is described in the framework of the Landau thermodynamic model as arising from a weak long-range antiferromagnetic state of martensite. Two volume magnetoelastic constants were estimated using the experimental values of the pressure derivatives ofTCAandTCM. A correlation between the signs of the pressure shifts ofTCA, andTCMand the distance between Mn-Mn nearest neighbours is established, which matches the empirical Castelliz-Kanomata diagram. The entropy change at martensitic transformation (MT), ΔSMT, grows up when the MT temperature,TM, is approachingTCAunder the influence of pressure, but under constant non-zero pressure this dependence is inverse.