Optimizing the composition of (Ce,La)(Co,Fe)for permanent magnet applications using density functional theory.

In this work, we calculated physical quantities, including the magnetocrystalline anisotropy constant () and magnetization (), for disordered (Ce,La)(Co,Fe)systems. Based on the results, we propose CeCoFeas the optimum composition for high-performance permanent magnets. The calculations employed the full-potential Korringa-Kohn-Rostoker Green's function method, and dealt with the compositional disorder of the systems within the coherent potential approximation. It was found that the La doping reducesat 0 K but increases the Curie temperature (), which leads to improvement of the magnetic properties at high temperatures. CeCoFehad the largest magnetic anisotropy of= 15.14 MJ/m, which is larger than that of CeCo(= 14.77 MJ/m).of CeCoFeestimated by the mean-field approximation was 1005 K, which exceeds that of CeCo(965 K). Further, our calculations showed that while doping of Fe destabilizes the system, CeCoFeis stable against decomposition into the simple substances. We also show calculated data that are informative for exploring high-performance permanent magnet materials in this paper.