Accelerated discovery and design of Fe-Co-Zr magnets with tunable magnetic anisotropy through machine learning and parallel computing

TL;DR

This paper introduces a machine learning and high-performance computing framework to discover new Fe-Co-Zr magnetic materials, identifying stable compounds with tunable magnetic properties for sustainable energy applications.

Contribution

It presents a scalable ML-assisted discovery method combining CGCNN and first-principles calculations to find new stable and metastable Fe-Co-Zr compounds with potential magnetic applications.

Findings

Discovered 9 new thermodynamically stable Fe-Co-Zr compounds.

Identified 81 promising metastable phases within 0.1 eV/atom of the convex hull.

Predicted compounds exhibit diverse crystal symmetries and magnetic behaviors.

Abstract

Rare earth (RE)-free permanent magnets, as alternative substitutes for RE-containing magnets for sustainable energy technologies and modern electronics, have attracted considerable interest. We performed a comprehensive search for new hard magnetic materials in the ternary Fe-Co-Zr space by leveraging a scalable, machine learning-assisted materials discovery framework running on GPU-enabled exascale computing resources. This framework integrates crystal graph convolutional neural network (CGCNN) machine learning (ML) method with first-principles calculations to efficiently navigate the vast composition-structure space. The efficiency and accuracy of the ML approach enable us to reveal 9 new thermodynamically stable ternary Fe-Co-Zr compounds and 81 promising low-energy metastable phases with their formation energies within 0.1 eV/atom above the convex hull. The predicted compounds span a wide range of crystal symmetries and magnetic behaviors, providing a rich platform for tuning functional properties. Based on the analysis of site-specific magnetic properties, we show that the Fe6Co17Zr6 compound obtained from our ML discovery can be further optimized by chemical doping. Chemical substitutions lead to a ternary Fe5Co18Zr6 phase with a strong anisotropy of K1 = 1.1 MJ/m3, and a stable quaternary magnetic Fe5Co16Zr6Mn4 compound.