High-potential magnetic anisotropy of CoPtCr-SiO2 perpendicular recording media

The magnetic anisotropy of CoPtCr-SiO2 perpendicular recording media, including higher energy terms, was studied as a function of film composition and seed layer materials. All series of CoPtCr films with various Cr content, deposited on Ru seed layers, show maximum values of total anisotropy K. at 25-30 at%Pt. The maximum value for CoPt(Cr = 0) films reaches similar to 15 X 10(6) erg/cm(3). The addition Of SiO2 to the CoPtCr films reduces the grain K., however the grain K. maintains a large value of 8 x 10(6) erg/cm(3) even when 10at% SiO2 is added to (Co90Cr10)(80)Pt-20, for instance, which indicates the high-potential thermal stability. Theoretical calculations for media designs of 400 Gbits/in(2) revealed that the ratio of the high-energy anisotropy term K-u2 to K-u1 (K-u = K-u1 + K-u2) is required to be 0.2-0.35 to enhance the energy barrier for the remanent state, without a notable change in switching field. The films deposited on Ru seed layers were found to show negligibly small K-u2 values, however, the values of K-u1 and Ku(2) vary significantly with the seed layer material used. K-u1 decreases almost linearly as the Ku(2) value increases. It is concluded that CoPtCr films have a sufficient potential in the values of K-u1 and Ku(2) for high-density perpendicular media.