Structures and magnetic properties of Co-Zr-B magnets studied by first-principles calculations

TL;DR

This study uses first-principles calculations and genetic algorithms to explore the structures and magnetic properties of Co-Zr-B alloys, identifying key motifs and doping strategies to enhance coercivity and anisotropy.

Contribution

It provides a comprehensive structural and magnetic analysis of Co-Zr-B alloys, revealing the role of boron doping and structural motifs in optimizing magnetic performance.

Findings

Co-Zr-B alloys share structural motifs with Co11Zr2 polymorphs.

Boron doping can significantly improve magnetocrystalline anisotropy.

Structural searches map energetics and magnetic moments across compositions.

Abstract

The structures and magnetic properties of the Co-Zr-B alloys near the Co5Zr composition were studied using adaptive genetic algorithm and first-principles calculations to guide further experimental effort on optimizing their magnetic performances. Through extensive structural searches, we constructed the contour maps of the energetics and magnetic moments of the Co-Zr-B magnet alloys as a function of composition. We found that the Co-Zr-B system exhibits the same structural motif as the "Co11Zr2" polymorphs, which plays a key role in achieving high coercivity. Boron atoms can either substitute selective cobalt atoms or occupy the interstitial sites. First-principles calculation shows that the magnetocrystalline anisotropy energies can be significantly improved through proper boron doping.