Cerium as a Possible Stabilizer of ThMn ₁₂-Type Iron-Based Compounds: A First-Principles Study

Abstract

The structural stability of CeFe₁₂ is investigated by using first-principles calculation. The formation energies of CeFe₁₂ relative to the Ce₂Fe₁₇ + Fe phase and to the CeFe₂ + Fe phase are calculated with the assumptions of trivalency and tetravalency for Ce. We compare them with corresponding results for Nd, Sm, and Zr. Our results suggest that the tetravalent Ce is a promising stabilizer of the ThMn₁₂ structure. We also show that the stabilizing effect depends as much on the valency as on the size of R (rare-earth) element by investigating RFe₁₂ where R is assumed to have a hypothetical valency.

Keywords: Permanent magnet, Rare earth, ThMn12 structure, First-principle calculation