Magnetic-field induced two-way shape memory effect of ferromagnetic Ni2MnGa sputtered films
Magnetic-field induced two-way shape memory effect of ferromagnetic Ni2MnGa sputtered films
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DOI：
10.2320/matertrans.47.625
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发表时间：
2006-03-01
影响因子：
1.2
通讯作者：
Itagaki, Kimio
中科院分区：
文献类型：
--
作者：
Ohtsuka, Makoto;Konno, Yuya;Itagaki, Kimio
磁场引起的形状记忆效应在物理学和应用领域具有重要的研究意义。采用四种Ni-Mn-Ga靶材，采用射频（RF）磁控溅射装置在聚乙烯醇（PVA）衬底上制备了不同成分的Ni2MnGa铁磁薄膜。从衬底分离后，薄膜在1073 K下加热3.6 ks进行均匀化处理，并在约束条件下在673 K下时效3.6 ks。对于不同成分的约束时效薄膜，通过热变化证实了可逆的双向SME。应变-温度曲线的梯度、伴随双向SME的应变量和热滞后的宽度与薄膜的组成有关。外加磁场作用下，应变-温度曲线向高温区移动，马氏体相得到稳定。此外，在约束时效膜冷却马氏体相变温度附近观察到磁场的双向SME，在应变-温度曲线上表现出较大的梯度和较小的热滞后。
The shape memory effect (SME) induced by the magnetic field is interesting and important for physics and application. The ferromagnetic Ni2MnGa films with various compositions were deposited on a poly-vinyl alcohol (PVA) substrate with a radio-frequency (RF) magnetron sputtering apparatus using four kinds of Ni-Mn-Ga targets. After separating from the substrate, the films were heat-treated at 1073 K for 3.6 ks for homogenization and aged at 673 K for 3.6 ks in a constraint condition. The reversible two-way SME by the thermal change was confirmed for the constraint-aged films with various compositions. The gradient of the strain-temperature curve, the amount of strain accompanied by the two-way SME and the width of thermal hysteresis were dependent on the composition of the films. The strain-temperature curve shifted to a high temperature region and the martensitic phase was stabilized by the applied magnetic field. Furthermore, the two-way SME by the magnetic field was observed around the martensitic transformation temperature on cooling for the constraint-aged film, which showed the large gradient and small thermal hysteresis in the strain-temperature curve.