Kainuma R, Imano Y, Ito W, Sutou Y, Morito H, Okamoto S, Kitakami O, Oikawa K, Fujita A, Kanomata T, Ishida K
Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba-yama, Sendai 980-8579, Japan.
Nature. 2006 Feb 23;439(7079):957-60. doi: 10.1038/nature04493.
Large magnetic-field-induced strains have been observed in Heusler alloys with a body-centred cubic ordered structure and have been explained by the rearrangement of martensite structural variants due to an external magnetic field. These materials have attracted considerable attention as potential magnetic actuator materials. Here we report the magnetic-field-induced shape recovery of a compressively deformed NiCoMnIn alloy. Stresses of over 100 MPa are generated in the material on the application of a magnetic field of 70 kOe; such stress levels are approximately 50 times larger than that generated in a previous ferromagnetic shape-memory alloy. We observed 3 per cent deformation and almost full recovery of the original shape of the alloy. We attribute this deformation behaviour to a reverse transformation from the antiferromagnetic (or paramagnetic) martensitic to the ferromagnetic parent phase at 298 K in the Ni45Co5Mn36.7In13.3 single crystal.
在具有体心立方有序结构的赫斯勒合金中观察到了大的磁场诱导应变，并且这种应变已通过由于外部磁场导致的马氏体结构变体的重排来解释。这些材料作为潜在的磁致动器材料已引起了相当大的关注。在此，我们报告了压缩变形的NiCoMnIn合金的磁场诱导形状恢复。在施加70 kOe的磁场时，材料中会产生超过100 MPa的应力；这样的应力水平大约比先前的铁磁形状记忆合金中产生的应力大50倍。我们观察到该合金有3%的变形并且几乎完全恢复到原始形状。我们将这种变形行为归因于在Ni45Co5Mn36.7In13.3单晶中，在298 K时从反铁磁（或顺磁）马氏体到铁磁母相的逆转变。
