CoPtCr-SiO_2垂直磁気記録媒体の結晶磁気異方性エネルギーの2次項K_<u2>と構造(磁気記録)

概要

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The higher energy term of magnetic anisotropy, K_<u2>, which is theoretically predicted to enhance thermal stability without a notable change in switching field, is discussed for CoPtCr-SiO_2 perpendicular recording media. CoPtCr films deposited on Ru seed layers show a high value of the first order energy term, K_<u1>. The K_<u1> value reaches 1.3×10^7 erg/cm^3 for Co_<70>Pt_<30> composition, for instance, whereas the K_<u2> values were found to be negligibly small irrespective of the film composition. However, it was revealed that the values of K_<u1> and K_<u2> vary significantly according to the seed layer material used. K_<u2> increases as the c/a of hcp-CoPtCr lattice of the film increases, whereas K_<u1> decreases as the c/a increases. This result implies that the appearance of K_<u2> is related to the elongation of the hcp-lattice or an increase in the stacking fault density. The addition of SiO_2 to the CoPtCr films reduces the values of K_<u1> and K_<u2>, however, no significant change in the value of K_<u2>/K_<u1> was observed on the addition of SiO_2 to CoCrPt films. It was concluded that CoPtCr-SiO_2 films have a sufficient potential in the values of K_<u1> and K_<u2> for high-density perpendicular media.
社団法人日本磁気学会の論文
2005-04-01