Micromagnetic study of Ni2MnGa under applied field (invited)
Micromagnetic study of Ni2MnGa under applied field (invited)
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DOI：
10.1063/1.373134
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发表时间：
2000-04
影响因子：
3.2
通讯作者：
Q. Pan;R. James
中科院分区：
文献类型：
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作者：
Q. Pan;R. James
本文用磁力显微镜对铁磁形状记忆合金Ni_2MnGa马氏体相的磁畴和孪晶结构进行了实验研究。在无磁场条件下冷却通过铁素体-马氏体相变后，由于退磁效应，具有{100}面的矩形试样始终采用具有表面浮凸的细尺度（101）孪晶结构。在2kOe的[010]场下冷却后，观察到完全不同的孪晶结构，由（110）条平行带组成，没有表面起伏。在2 ~ 8.5kOe的增磁场下，观察到了如下的畴结构序列：孪晶带中的杉树型畴、孪晶边界上的杉树型畴、厚壁单畴（约100000）。0.5μm），与孪晶边界一致。畴壁表现出异常高的对比度，有证据表明，不规则间隔的节点的壁子结构。这些观察结果与理论上的微磁系统是一致的。
We present an experimental study of the domain and twin structure in the martensitic phase of the ferromagnetic shape memory alloy Ni2MnGa using magnetic force microscopy. After cooling through the austenite–martensite transformation under no field, a rectangular specimen with {100} faces consistently adopted a structure of fine-scale (101) twins with surface relief, due to demagnetization effects. After cooling under a [010] field of 2 kOe, a completely different twin structure consisting of (110) parallel bands with no surface relief was observed. Under increasing fields between 2 and 8.5 kOe, the following sequence of domain structures were observed: fir tree patterns in twin bands, fir tree patterns localized at twin boundaries, single domains with thick walls (approx. 0.5 μm) coincident with twin boundaries. The domain walls exhibit unusually high contrast, and there is evidence for a wall substructure with irregularly spaced nodes. These observations are consistent with a theoretical micromagnetic s...