Using small-angle neutron scattering to probe the local magnetic structure of perpendicular magnetic recording media

Small-angle neutron scattering (SANS) has been used to measure the local magnetic structure of perpendicular media consisting of granular Co Cr Pt - Si O x thin films. The dimensions of the magnetic structures determined by SANS are consistent with the physical grain sizes suggested by transmission electron microscopy measurements, but yield additional information on magnetic structure within the grains, including the existence of a much smaller magnetic core. The results are similar to those recently obtained on longitudinal magnetic recording media, but with the addition of strong interference terms due to the narrower distribution of grain sizes in these samples.