Abstract
Using dc-magnetron sputtering, Fe, Co, and Cu were sputtered on a glass substrate. The samples were annealed at 500°C in a vacuum, air, or nitrogen atmosphere. It was found that the samples annealed in nitrogen showed a coercive force of over 200 kA/m.
Hysteresis loop measurements and the results of ESCA and X-ray diffraction analysis seem to suggest that Co-Fe2O4 ferrite was the major magnetic component formed by the residual oxygen during annealing.
On this assumption, the O2 pressure during annealing was altered, and it was found that the coercive force increases as the oxygen pressure decreases, and that it reaches 115 kA/m when the oxygen pressure is about 8 m Torr.
