Magnetic Microstructure Analysis of Ferromagnetic Shape Memory Alloys and Related Compounds
Magnetic Microstructure Analysis of Ferromagnetic Shape Memory Alloys and Related Compounds
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DOI：
10.4028/www.scientific.net/msf.684.117
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发表时间：
2011-05
期刊：
影响因子：
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通讯作者：
Yasukazu Murakami;R. Kainuma;D. Shindo;A. Tonomura
中科院分区：
文献类型：
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作者：
Yasukazu Murakami;R. Kainuma;D. Shindo;A. Tonomura
我们对镍基铁磁形状记忆合金进行了磁成像。用Lorentz显微镜和电子全息术揭示了样品的磁性结构，这两种方法是建立在透射电子显微镜基础上的强有力的工具。对母相具有L21有序结构的Ni51Fe22Ga27和Ni50Mn25Al12.5Ga12.5合金的观察表明，由于原子有序的降低，反相界(即一种平面缺陷)引起了磁化强度分布的显著变化，实际上，这些合金的磁化强度取决于化学有序的程度。我们提出了一种基于透射电子显微镜观察的方法来估计重要的磁性参数(磁晶各向异性常数和交换刚度常数)。这种方法在传统技术无法应用的纳米尺度区域的磁测量中应该是有用的。
We performed magnetic imaging of Ni-based ferromagnetic shape memory alloys. The magnetic microstructure was revealed by Lorentz microscopy and electron holography, which are powerful tools based on transmission electron microscopy. Observations of Ni51Fe22Ga27 and Ni50Mn25Al12.5Ga12.5 alloys, both of which have an L21-ordered structure in the parent phase, demonstrated that the antiphase boundaries (i.e., a type of planer defects) caused significant changes in the magnetization distribution due to depression of the atomic order—actually, the magnetization in these alloys depends upon the degree of chemical order. We propose a method which estimates the important magnetic parameters (the magnetocrystalline anisotropy constant and exchange stiffness constant) based on transmission electron microscopy observations. This method should be useful in magnetic measurements of nanometer-scale areas, for which conventional techniques cannot be applied.