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

Abstract

The spin-polarized electronic energy bands, densities of states, and magnetic moments of the intermetallic compounds YCo"SmCo"and GdCo, 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.

Calculation of magnetic anisotropy energy inSmCo5

“…A smaller portion of the MAE can be associated with the Co-d band anisotropy, related to the peak in the density of states at the Fermi energy. Our result for the MAE of SmCo5, 21.6 meV/f.u., agrees reasonably with the experimental value of 13-16 meV/f.u., and the calculated magnetic moment (including the orbital component) of 9.4µB agrees with the experimental value of 8.9µB .The permanent magnet intermetallic compound SmCo 5 has been studied extensively experimentally 1,2 and theoretically [3][4][5][6][7][8][9][10][11] . The interest in these materials is fueled by their large magnetic anisotropy energy (MAE), which is defined as the difference between the groundstate energies due to rotation of the magnetic field (magnetization direction).…”

“…The permanent magnet intermetallic compound SmCo 5 has been studied extensively experimentally 1,2 and theoretically [3][4][5][6][7][8][9][10][11] . The interest in these materials is fueled by their large magnetic anisotropy energy (MAE), which is defined as the difference between the groundstate energies due to rotation of the magnetic field (magnetization direction).…”

Perpendicular magnetic anisotropy in amorphous NdxCo1−x thin films studied by x-ray magnetic circular dichroism

“…This high structural disorder might explain the susceptibility of the speromagnetic neodymium in these films, which is lower than the observed for metallic neodymium [53]. The magnetic interaction between neodymium atoms is believed to be mediated by their 5d orbitals [54,66], whose overlap and delocalization decreases with disorder, consequently decreasing the intensity of their magnetic interaction. …”

“…Such a specific number of holes has been obtained taking into account that the estimated proportion of neodymium atoms bonded to cobalt in sample NC5 is about 25% (the details of this estimation are given in Sec. III D 1) and the expected transferred charge per neodymium atom is, theoretically, not higher than 1 electron [54]. This quantity might be overestimated since indirect experimental measurements suggest values lower than 0.5 electrons [55].…”

Magnetic structure and anisotropy of Ga- and Al-substitutedLaCo5andYCo5Može1, Pareti2, Paoluzi3 et al. 1996Phys. Rev. B32390View full textAdd to dashboardCite

“…This is reflected in the observed site moments for both YCo 4 Ga and LaCo 4 Ga as well as in the behavior of the magnetocrystalline anisotropy. The various band structure calculations 8,9,[20][21][22] do not take into consideration the different site symmetries for the 2c(6m2) and 3g(mmm) positions, while calculation of the magnetic anisotropy for these systems is still a formidable task.…”