CoPtCr − SiO 2 media with Ku2 magnetic anisotropy term fabricated with Pd seed layers

Abstract

We tried to enhance the grain isolation of CoPtCr–SiO2 media with Pd seed layers while simultaneously inducing the second energy term of the uniaxial anisotropy, Ku2. The addition of 5%N2 to the Ar gas used during the deposition of the Pd seed layer was found to reduce the Pd grain size. This structural change in the seed layer enhances the grain isolation of CoPtCr, without degrading the c-axis orientation, while simultaneously inducing a Ku2 component. However, adding N2 gas to the Pd seed layer increases the CoPtCr grain size to about 10nm. Moreover, these media have magnetization curves with relatively low squareness, this is related to the appearance of a cone state of magnetization induced by the Ku2 term. Magnetic analysis revealed that, in addition to a reduction of the grain size, a reduction of the saturation magnetization is also necessary to realize practical CoPtCr–SiO2 media, which take advantage of the Ku2 term.