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

Experimental characterization of the magnetic anisotropy field of grains H
_k
^grain
, and the intergranular magnetic coupling in (Co
₈₆
Cr
₁₂
Ta
₂
)
_100-x
Pt
_x
thin film media was carried out by analyses of the magnetic torque and ΔM plot. The magnitude of H
_k
^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 H
_c
to H
_k
^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 H
_c
to H
_k
^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 H
_k
^grain
should be taken into account, in order to clarify how much the intergranular magnetic coupling influences the coercive force through analysis of ΔM plot.