Evolutionary search for cobalt-rich compounds in the yttrium-cobalt-boron system

Modern high-performance permanent magnets are made from alloys of rare earth and transition metal elements, large magnetization is achieved in the with high concentration metals. We applied evolutionary search scheme based on first-principles calculations to Y-Co-B system predicted 37 cobalt-rich compounds probability being stable. Focusing remarkably compounds, YCo$_{16}$ YCo$_{20}$, we found that, although they metastable phases, phase stability increased increase temperature due contribution vibrational entropy. The Curie higher by 0.22 T 204 K 0.29 YCo$_{20}$ than those Y$_{2}$Co$_{17}$ which has been well studied as strong magnetic compounds.