Effect of Annealing on the Magnetic Properties of Co/Fe Multilayer Films Deposited with Different Background Pressures

The effects of post-deposition annealing on the magnetic properties of Co/Fe multilayer films sputtered with different background pressures (PB) were examined. Films were deposited by dc magnetron sputtering with a PB of 1.0×10^¿6 or 9.0×10^¿8 Torr, and were annealed in vacuum at temperatures between 100°C and 600°C for one hour. The saturation magnetization of films increased on annealing at and above 300°C, indicating the alloying of Co and Fe. The coercivity (Hc) of films deposited in a high PB was 1 Oe before annealing, but increased on annealing at and above 300°C. The Hc of films deposited in a low PB was 50 Oe before annealing, but decreased rapidly when annealed at and above 200°C, reaching a minimum of 8 Oe at 500°C. The differences in magnetic properties for differnet PB are mainly due to the different oxygen contents of the films.