Quantification and spatial distribution of noise in written transitions measured with magnetic force microscopy

Magnetic Force Microscope (MFM) imaging data has been mathematically processed to quantify noise in written transitions in thin-film media. The method also yields the spatial distribution of the noise. To demonstrate the technique, we analyzed dibit transition pairs written with varying intertransition spacings. The spatial noise profiles and recording density dependence of the noise as measured from MFM images are in excellent agreement with both recording measurements and micromagnetic modeling. Processed MFM image data confirms that the minimum inter-transition spacing is limited by the media magnetic cluster size. This cluster size correlates well with the spacing at which the transition noise is maximum and severe percolation occurs.