Improved magnetostriction in Galfenol alloys by aligning crystal growth direction along easy magnetization axis
Chao Zhou, Yapeng Liu, Kaiyun Chen, Zhiyong Dai, Tianyu Ma, Yu Wang, Shuai Ren, Junkai Deng, Rui Zhang, Fanghua Tian, Yin Zhang, Hao Zeng, Sen Yang
Abstract
Abstract Galfenol (Iron-gallium) alloys have attracted significant attention as the promising magnetostrictive materials. However, the as-cast Galfenols exhibit the magnetostriction within the range of 20–60 ppm, far below the requirements of high-resolution functional devices. Here, based on the geometric crystallographic relationship, we propose to utilize the 90°-domain switching to improve the magnetostriction of Galfenols by tuning the crystal growth direction (CGD) along the easy magnetization axis (EMA). Our first-principles calculations demonstrate that Pt doping can tune the CGD of Galfenol from [110] to [100], conforming to the EMA. Then, it is experimentally verified in the (Fe 0.83 Ga 0 . 17 ) 100 −x Pt x ( x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) alloys and the magnetostriction is greatly improved from 39 ppm ( x = 0, as-cast) to 103 ppm ( x = 0.8, as-cast) and 188 ppm ( x = 0.8, directionally solidified), accompanying with the increasing CGD alignment along [100]. The present study provides a novel approach to design and develop high-performance magnetostrictive materials.