Magnetic Anisotropy and Intergranular Magnetic Coupling in (Co86Cr12Ta2)100-xPtx Thin Film Media

Experimental characterization of the magnetic anisotropy field of grains Hk^grain, and the intergranular magnetic coupling in (Co86Cr12Ta2)100-xPtx thin film media was carried out by analyses of the magnetic torque and ¿M plot. The magnitude of Hk^grain gradually increases from about 4 kOe to around 8 kOe with increasing Pt content up to 8 at%, mainly because of the increase in magnetocrystalline anisotropy. On the other hand, the ratio of the coercive force Hc to Hk^grain changes from about 0.2 to about 0.3, depending on the Pt content and substrate temperature at the time of the film´s fabrication. It was clarified that the difference of the ratio of Hc to Hk^grain in the examined media depends mainly on the difference in the strength of the intergranular exchange coupling. On the other hand, it is suggested that the knowledge of Hk^grain should be taken into account, in order to clarify how much the intergranular magnetic coupling influences the coercive force through analysis of ¿M plot.