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arXiv · 1906.11329

Concentration tuned tetragonal strain in alloys: application to magnetic anisotropy of FeNi$_{1-x}$Co$_x$

Aleksander L. Wysocki·Manh Cuong Nguyen·Cai-Zhuang Wang·Kai-Ming Ho·Andrey V. Postnikov·Vladimir P. Antropov
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Abstract

We explore an opportunity to induce and control tetragonal distortion in materials. The idea involves formation of a binary alloy from parent compounds having body-centered and face-centered symmetries. The concept is illustrated in the case of FeNi$_{1-x}$Co$_x$ magnetic alloy formed by substitutional doping of the L1$_0$ FeNi magnet with Co. Using electronic structure calculations we demonstrate that the tetragonal strain in this system can be controlled by concentration and it reaches maximum for $x=0.5$. This finding is then applied to create a large magnetocrystalline anisotropy (MAE) in FeNi$_{1-x}$Co$_x$ system by considering an interplay of the tetragonal distortion with electronic concentration and chemical anisotropy. In particular, we identify a new ordered FeNi$_{0.5}$Co$_{0.5}$ system with MAE larger by a factor 4.5 from the L1$_0$ FeNi magnet.

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Aleksander L. Wysocki, Manh Cuong Nguyen, Cai-Zhuang Wang, Kai-Ming Ho, Andrey V. Postnikov, Vladimir P. Antropov. 2019-06-26. Concentration tuned tetragonal strain in alloys: application to magnetic anisotropy of FeNi$_{1-x}$Co$_x$. https://doi.org/10.1103/physrevb.100.104429

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