Nitrogen plasma treatment in two-step temperature deposited FePt bilayer media

Top view of grains in the samples Ref, Ref_BL, A1, N1 and N2 (inset shows grain size distribution histogram). The averaged mean grain size (xc) and the FWHM of the grain size distribution are indicated in the bottom-left. (f) Plot for the averaged mean grain size and change in grain size distribution (%) of all the samples. The change in grain size distribution is calculated compared to that of the sample Ref (indicated by reference line at zero).