Magnetic characterisation of thin film recording media

The basic magnetic characterization techniques for thin recording media are critically examined in relation to the requirements for modern high-storage-density materials. The applicability and usefulness of remanence curves for the characterization of thin-film media are discussed together with the recently developed ΔI(H ) technique. The origins of the relation between these measurements and cooperative reversal are presented, together with the improved data showing the correlation between ΔI(H) and noise. This discussion is extended to include the time-dependent phenomena and in particular the activation volume, including the effects of intergranular coupling. Data are presented to show these effects in both single-layer alloy films and laminated systems, and the implications for ultimate recording density are discussed