Spin-polarized energy-band structure of YCo5, SmCo5, and GdCo5

Abstract

The spin-polarized electronic energy bands, densities of states, and magnetic moments of the intermetallic compounds Y${\mathrm{Co}}_5$, Sm${\mathrm{Co}}_5$, and Gd${\mathrm{Co}}_5$ are calculated by a self-consistent augmented-plane-wave method. The results are similar in the three cases, with the computed magnetic moments in reasonable agreement with experiment. Only about one electron (of a possible three) is transferred from the rare earth to cobalt, leaving the minority-spin cobalt $3d$ band unfilled, and the moment high. There is evidence of $d-d$ coupling between cobalt and the rare earth, providing information as to why experiments designed to reverse the antiparallel spin coupling between the two sublattices by manipulation of the electron concentration have been unsuccessful.