Establishment of anisotropy control method of the magnetostrictive thin film using stress induced by difference in thermal expansion and their application for highly sensitive strain sensor.

在这项研究中，对于软磁致伸缩薄膜（FeSiB），单轴各向异性的控制方法，使用的热膨胀系数的差异组成的其他磁致伸缩膜（Mo）的层状结构进行了研究，以实现高灵敏度的应变传感器。当对膜进行退火以释放残余应力时，磁性膜和非磁性膜的热膨胀系数的差异彼此产生内应力。由于逆磁致伸缩效应，内应力可以诱导磁性薄膜沿任意方向的各向异性，发现矩形Mo层沿宽度方向诱导单轴各向异性。此外，观察到随着矩形Mo底层的长轴的延长，FeSiB膜的面内单轴各向异性逐渐增强。此外，利用该方法还观察到了FeSiB在环形样品中径向诱导的各向异性。

In this study, for a soft magnetostrictive thin film (FeSiB), uniaxial anisotropy control method using a difference of thermal expansion coefficients of layered structure composed of other nonmagnetic film (Mo) was studied for realizing high sensitive strain sensor. When the film is subjected to annealing to release a residual stress, the differences of the thermal expansion coefficient of the magnetic film and nonmagnetic film produce an inner stress to each other. The inner stress can induce anisotropy of the magnetic film to arbitrary direction due to the inverse magnetostriction effect.It is found that the uniaxial anisotropy is induced to width direction of the rectangular Mo layer. In addition, it was observed that as the major axis of the rectangular Mo under layer was lengthened, the in-plane uniaxial anisotropy of the FeSiB film was gradually strengthened. Furthermore, the anisotropy of FeSiB induced radially of a ring shape sample using this method was observed.