Rare-Earth Orbital Moment Contributions To The Magnetic Anisotropy In Magnetostrictive Tb0.3dy0.7fe2

Soft x-ray Magnetic Circular Dichroism spectroscopy at the Dy and TbM4 , 5 and the FeL2 , 3 edges was performed on a sputter deposited polycrystalline Terfenol-D (Tb0.3Dy0.7Fe2) film on sapphire substrates at temperatures from 100 to 300K to evaluate the elementwise contribution to the magnetocrystalline anisotropy and coercive field. The elemental spin and orbital magnetic moments were calculated using the x-ray Magnetic Circular Dichroism sum rules. As temperatures decreased, the Tb and Fe moments plateau at 200K with values of 7.6 mu (B)/atom and 1.8 mu (B)/atom, respectively, while the Dy moment increases to 8.9 mu (B)/atom at 100K. Between 300 and 200K, the change in magnetic anisotropy is dominated by thermally induced magnetoelastic effects while for temperatures below 200K magnetocrystalline anisotropy (MCA) changes are dominant. The MCA changes below 200K appear to be due to increases in the Dy orbital moment with decreasing temperature in this temperature regime.