Magnetic and structural phase transitions in the shape-memory ferromagnetic alloys Ni2+xMn1-xGa
Magnetic and structural phase transitions in the shape-memory ferromagnetic alloys Ni2+xMn1-xGa
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DOI：
10.1134/1.558877
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发表时间：
1999-05-01
影响因子：
1.1
通讯作者：
Buchel'nikov, VD
中科院分区：
文献类型：
--
作者：
Bozhko, AD;Vasil'ev, AN;Buchel'nikov, VD
报告了形状记忆铁磁合金 Ni2+xMn1-xGa (x=0-0.20) 中磁化率和电阻率与温度依赖性的实验研究结果。 T-x 相图是根据这些数据构建的。结果表明，用 Ni 部分替代 Mn 会导致结构（马氏体）T-M 和磁性 T-C（居里点）相变温度收敛。在 T-C=T-M 区域，转变温度在 0 至 10 kOe 范围内随磁场线性增加。研究了磁场诱导马氏体相变的动力学，并测量了直接和反向转变过程中马氏体-奥氏体相界的速度。提出了理论模型并计算了T-x相图。结果表明，存在磁相变和马氏体相变合并为一级相变的浓度范围。理论结果与实验定性一致。 (C) 1999 年美国物理研究所。 [S1063-7761(99)01605-4]。
The results of an experimental investigation of the temperature dependences of the magnetic susceptibility and resistivity in the shape-memory ferromagnetic alloys Ni2+xMn1-xGa (x=0-0.20) are reported. A T-x phase diagram is constructed on the basis of these data. It is shown that partial substitution of Ni for Mn causes the temperatures of the structural (martensitic) T-M and magnetic T-C (Curie point) phase transitions to converge. In the region where T-C=T-M the transition temperature increases linearly with magnetic field in the range from 0 to 10 kOe. The kinetics of a magnetic-field-induced martensitic phase transition is investigated, and the velocities of the martensite-austenite interphase boundary during direct and reverse transitions are measured. A theoretical model is proposed and the T-x phase diagram is calculated. It is shown that there exist concentration ranges where the magnetic and martensitic transitions merge into a first-order phase transition. The theoretical results are in qualitative agreement with experiment. (C) 1999 American Institute of Physics. [S1063-7761(99)01605-4].