PERPENDICULAR MAGNETIC-ANISOTROPY IN SPUTTERED GDCO FILMS

Strong perpendicular magnetic anisotropy has been observed in GdCo films deposited by zero-bias sputtering with an Ar-N2 gas. As the nitrogen partial pressure of the sputtering gas increases, the perpendicular anisotropy constant increases and the Co sublattice moment of the films becomes large. The saturation magnetization of the films shows a steep temperature dependence near the magnetic compensation temperature. A molecular field theory indicates that the steep temperature dependence arises from the change in the exchange constant for the Gd-Co interaction. The perpendicular anisotropy may result from the exchange constant change.