CoPtCr-SiO/sub 2/ perpendicular media for high density recording with a high order magnetic anisotropy energy term

Abstract

The first and second order energy terms of uniaxial magnetic anisotropy, K/sub u1/ and K/sub u2/, of CoPtCr-SiO/sub 2/ perpendicular recording media were studied as a function of film composition and film structure. Moreover, the fabrication of CoPtCr-SiO/sub 2/ media having adequate values of K/sub u1/ and K/sub 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/sub u1/ and K/sub u2/ varied significantly with the seed layer material used, probably due to epitaxial growth of CoPtCr on the seed layers. K/sub u2/ increased, accompanied by a reduction in K/sub u1/ as the c/a ratio of the hcp-CoPtCr lattice increased. Moreover, experimental results suggest that a high stacking-fault density enhances the K/sub u2/ values, especially in the high Pt content region. The addition of SiO/sub 2/ reduces the total anisotropy, K/sub u1/+K/sub u2/, but no significant change in the ratio of K/sub u2//K/sub u1/ was observed. The fabrication of CoPtCr-SiO/sub 2/ media with adequate values of K/sub u1/ and K/sub u2/ was successfully demonstrated, although more intensive efforts to enhance grain isolation are required to confirm the advantages conferred by the K/sub u2/ term.