Prediction of intrinsic properties of Fe-doped CeCo₅

Due to high uniaxial anisotropy and abundant nature of Ce, CeCo₅ has become a subject of intense research for getting an excellent permanent magnet with low cost. CeCo₅ comes under the materials having a crystal structure of CaCu₅-type with space group P6/mmm. The changes in the valence state of the Ce atom from +4 to +3 due to the presence of Cu in CeCo₅ can enhance the coercivity of CeCo_5-xCu_x. The replacement of Co-atom by another transition metal can manipulate the magnetization. The first principles calculations were performed to study the effect of Fe-doping on the magnetic properties of CeCo_4.5-xFe_xCu_0.5 to increase the magnetic moment with sufficient anisotropy. Fe doping increases the total moment. The anisotropy is highly dependent on the sites occupied by Fe and Cu. 20% Fe gives high uniaxial anisotropy in CeCo_4.5-xFe_xCu_0.5 for Cu at the 3g site, whereas 10% Fe in CeCo_4.5-xFe_xCu_0.5 gives high uniaxial anisotropy for Cu at the 2c. Site preference of Fe is also checked for the compounds separately with Cu at 2c and 3g sites. Depending upon the concentration, Fe prefers both 3g and 2c sites in a CeCo_4.5-xFe_xCu_0.5 indicating the importance of the structural geometry.