Writing and reading perpendicular magnetic recording media patterned by a focused ion beam

We have written and read bit patterns on arrays of square islands cut with a focused ion beam into granular perpendicular magnetic recording media. Using a static write-read tester, we have written square-wave bit patterns on arrays of islands with sizes between 60 and 230 nm, matching the recording linear density to the pattern period. These measurements reveal the onset of single-domain behavior for islands smaller than 130 nm, in agreement with magnetic force microscope images. The recording performance of patterned regions is systematically compared to that of unpatterned regions. (C) 2001 American Institute of Physics.