Temperature dependence of the anisotropy of amorphous NdCo5 thin films

The magnetic anisotropy energy of the Co sublattice of amorphous NdCo5 thin films deposited by magnetron sputtering has been measured in 30nm thick films from 220K up to 420K using the magneto-optical transverse Kerr effect (TMOKE). They had a strong perpendicular magnetic anisotropy, with an anisotropy energy of 2X106erg/cm3 at room temperature. The increase in the perpendicular anisotropy energy when the temperature decreased was smaller than expected if it was mainly caused by the Nd ions. An irreversible decrease in the anisotropy energy was observed when the films were annealed to only 420K. Such a change was accompanied by an increase in the magnetic moment of Co, indicating that the origin of the perpendicular anisotropy in these films has to be associated with an asymmetry in the local atomic environment of Co and Nd induced during the deposition process.