High linear density written transitions in exchange isolated Pt/CoCrTa multilayer thin films

Multilayer Pt/CoCrTa thin-film structures have been prepared which display little intergranular exchange coupling and nearly 100% remanence in the perpendicular direction. Magnetic recordings of continuous square wave patterns have been made and characterized using an inductive contact recording transducer and by magnetic force microscopy. Written transitions appear to retain good fidelity at more than 300 000 transitions per inch. With exchange isolation of the grains, media noise becomes negligible relative to thermal noise from the recording system electronics. Analysis of magnetic force microscopy images yields a signal to integrated noise ratio of 17 dB at 309 000 transitions per inch written in a 4 mu m wide track, which is comparable to a measured signal to total noise ratio of 8 dB at 350 000 reversals per inch measured using an inductive transducer at 100 in./s. These results are contrasted with observations on exchange coupled Pt/Co multilayers. (C) 1996 American Institute of Physics.