Enhancement of grain isolation by interlayer diffusion in AFC media with CrMo spacer layer

It was found that a reduction in M_rt can be obtained in the new antiferromagnetically coupled (AFC) medium with a CrMo spacer layer due to antiferromagnetic (AF) coupling, which is similar to the conventional AFC medium with a Ru spacer layer. From the results of ΔM and magnetic force microscopy (MFM), it was found that the intergranular exchange coupling decreases when CrMo is used as a spacer layer. Micromagnetic simulations of ΔM and MFM analyses gave consistent results with experiment, i.e., 1) AFC media with higher intergranular exchange coupling constant have larger magnetic cluster and higher ΔM peak and 2) the media with higher AF coupling constant have smaller magnetic cluster and smaller ΔM. In this paper, we propose that the media noise of the AFC media with a CrMo spacer layer may be improved by a reduction in the magnetic cluster size, due to the decrease of the intergranular exchange coupling between magnetic grains.