CoPtCr-SiO2 perpendicular media for high density recording with a high order magnetic anisotropy energy term

The first and second order energy terms of uniaxial magnetic anisotropy, K-u1 and K-u2, of CoPtCr-SiO2 perpendicular recording media were studied as a function of film composition and film structure. Moreover, the fabrication of CoPtCr-SiO2 media having adequate values of K-u1 and K-u2 for high recording density was preliminarily studied. An analysis of CoPtCr films with various kinds of seed layer materials revealed that the values of K-u1 and K-u2 varied significantly with the seed layer material used, probably due to epitaxial growth of CoPtCr on the seed layers. K-u2 increased, accompanied by a reduction in K-u1 as the c/a ratio of the hep-CoPtCr lattice increased. Moreover, experimental results suggest that a high stacking-fault density enhances the K-u2 values, especially in the high Pt content region. The addition of SiO2 reduces the total anisotropy, K-u1 + K-u2, but no significant change in the ratio of K-u2/K-u1 was observed. The fabrication of CoPtCr-SiO2 Media with adequate values of K-u1 and K-u2 was successfully demonstrated, although more intensive efforts to enhance grain isolation are required to confirm the advantages conferred by the K-u2 term.