Abstract The over tenfold magnetostriction enhancement by soluting nonmagnetic Ga into body centered cubic (BCC) Fe has been ascribed to crystal lattice softening, which indicates that the Fe-Ga solid solution lies in the crossover of martensitic transformation. Identifying the martensitic phase then becomes essential. Here we report the stress-induced local six-layer modulated monoclinic (6 M) martensites in a Fe79Ga21 alloy solution-treated at 1373 K. Although X-ray diffraction (XRD) and magnetic measurements reveal that the bulk sample exhibits BCC average structure, the transmission electronic microscopy (TEM) characterizations however show that the mechanically grinded foil sample contains local 6 M phase. First principal calculations suggest that low formation energy barrier between the ordered D03 and the 6 M phases are responsible for the stress-induced structural transformation. Our work provides evidence for the lattice softening of Fe-Ga solid solution, adding important insight into understanding the origin of its extraordinary magnetostriction enhancement.

中文翻译：

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Fe-Ga 磁致伸缩合金晶格软化的证据：应力诱导的局部马氏体

摘要 通过将非磁性 Ga 溶解到体心立方 (BCC) Fe 中，超过十倍的磁致伸缩增强归因于晶格软化，这表明 Fe-Ga 固溶体位于马氏体转变的交叉中。识别马氏体相变得至关重要。在这里，我们报告了在 1373 K 下固溶处理的 Fe79Ga21 合金中应力诱导的局部六层调制单斜 (6 M) 马氏体。 尽管 X 射线衍射 (XRD) 和磁测量显示大块样品表现出 BCC 平均结构，然而，透射电子显微镜 (TEM) 表征表明机械研磨的箔样品包含局部 6 M 相。第一个主要计算表明，有序 D03 和 6 M 相之间的低形成能垒是应力诱导结构转变的原因。我们的工作为 Fe-Ga 固溶体的晶格软化提供了证据，为理解其非凡的磁致伸缩增强的起源增加了重要的洞察力。