Computational screening of Fe-Ta hard magnetic phases

TL;DR

This study uses computational methods to identify new Fe-Ta magnetic phases with potential for permanent magnets, discovering stable and metastable structures with promising magnetic properties.

Contribution

The paper introduces a systematic computational approach to discover novel Fe-Ta magnetic phases, including stable and metastable structures with high magnetization and anisotropy.

Findings

Identified two new stable magnetic phases: tetragonal Fe₃Ta and cubic Fe₅Ta.

Discovered metastable phases Fe₅Ta₂ and Fe₆Ta with properties comparable to known permanent magnets.

Predicted high saturation magnetization and magnetocrystalline anisotropy in the new phases.

Abstract

In this work we perform a systematic calculation of the Fe-Ta phase diagram to discover novel hard magnetic phases. By using structure prediction methods based on evolutionary algorithms, we identify two new energetically stable magnetic structures: a tetragonal Fe$_3$Ta (space group 122) and cubic Fe$_5$Ta (space group 216) binary phases. The tetragonal structure is estimated to have both high saturation magnetization ($\mu_0$M$_s$=1.14 T) and magnetocrystalline anisotropy (K$_1$=2.17 MJ/m$^3$) suitable for permanent magnet applications. The high-throughput screening of magneto-crystalline anisotropy also reveals two low energy metastable hard magnetic phases: Fe$_5$Ta$_2$ (space group 156) and Fe$_{6}$Ta (space group 194), that may exhibit intrinsic magnetic properties comparable to SmCo$_5$ and Nd$_2$Fe$_{14}$B, respectively.