Experimental Characterization of Intergranular Exchange Coupling in CoCrTaPt and CoNiCrPt Thin Film Media

Abstract

Abstract-Quantitative characterizations of magnetic anisotropy of grains and intergranular coupling were carried out in (C0 86 Cr 12 Ta:0100-XPt x (X= 1-9) and (Co 62.sNi 30 Cr 75) lOO-XPtX (X=O-16) thin film media, by magnetic torque and AM analyses. In both materials, magnetocrystalline anisotropy field of grains Hkgrain increases twice as large as those of X=O with increasing X to about 9at%, which plays a main role in increasing He-However, Hc/Hkgrain decreases with increasing X in both media. In CoCrTaPt media, the decrement of Hc/H kgrain is found to be mainly caused by the increment of intergranular exchange coupling. In CoNiCrPt media, it is suggested that the change of c-axes directions from in plane to normal mainly causes the decrement in Hc/Hkgrain. Furthermore, to examine the effect of intergranular coupling on magnetic properties by means of 6M plot, it is clarified that the difference of H kgrain should be taken into account.