ΔH(M, ΔM) method for the determination of intrinsic switching field distributions in perpendicular media

We describe a method for the experimental characterization of intrinsic switching field distributions in perpendicular media. The method is based upon a comparison between the major loop and a set of recoil loops, which start at a certain distance AM away from saturation. In particular, we measure the applied field difference Delta H between the recoil loops and the major loop at identical M values, for which the average demagnetizing fields are the same. By analyzing complete Delta H(M, Delta M) data sets taken from multiple recoil loops, we gain a detailed measure of the intrinsic switching field distribution D(H-S). Using polar-Kerr effect measurements of recording disk samples, we demonstrate the capabilities of our approach.