Magnetic Properties and Structure for Compositionally Modulated Co-CoOx Films

To clarify the influence of CoO spins on the magnetic properties of Co-CoO reactive-sputtered films, Co-CoO_x compositionally modulated (CM) films were investigated. These Co-CoO_x CM films were prepared by modulating the oxygen partial pressure (Po₂) in the vacuum chamber. These films have Co-CoO interfaces parallel to the film plane. The coercivity (H_c) and in-plane anisotropy (K_H) of CM films with short modulation periods increased remarkably below the Néel temperature of CoO (= 292 K). These increases in H_c and K_H at low temperatures are thought to originate in a magnetic interaction between the Co spins and CoO spins.