Magnetic structures in Co-Cr films for perpendicular recording

Recently it has been shown that the areal density of Co-Cr media for perpendicular recording using a single pole head can be in the order of 5-10 Gbit/inch² [1]. In this laboratory demonstration a track pitch of 0.5 μm (50 kTPI) and a bit length of 260 nm (100 kFRPI) was achieved. Using the same recording set-up, in this paper a MFM image is shown using 300 kFRPI linear bit density and a track width of 0.4 μm. With these densities, icrostructural features like columnar size, compositional separation of Co and Cr, magnetic coupling and reversal behaviour become more and more important. This paper presents experimental results obtained from Co-Cr thin films by using MFM, study of artificially etched micro-strips and measuring anomalous Hall effect from submicron structures, as well as results obtained from magnetostatic and micromagnetic simulations.