Effects of Doping on Magnetic Properties of YCo_(5-x)Fe_x and YCo_(5-x)Ag_x——First Principles Calculation

摘要

One way of improving the magnetic properties of RECo_5(RE = rare earth) compounds, especially the magnetic anisotropy energy (MAE) , is to dope them with some additives such as Fe, Ni, Cu. Those dopants bring changes in both lattice geometry and magnetic properties of the compounds. In this paper, the effects of doping on Yco_(5-x)Fe_x and Yco_(5-x) Ag_x were studied in two simple but effective ways: first, the geometric effect induced by doping and then, the pure doping role namely without any geometric changes. The calculated results indicate that the magnetic moments of Co show a transition from a high spin state to a low one with the change of the volume of the cell in all Yco_5, Yco_3Fe_2 and Yco_3Ag_2 alloys. The change of c/a ratio with constant lattice parameter a also influences drastically the magnetic moments and the MAE. As the geometric structure is not changed, it is found that the doping effects of magnetic element Fe and non-magnetic element Ag are quite different.