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A survey of various measurement techniques, including the rotation method, the hard-axis hysteresis loop, and the torque measurement, is presented using Co∕Pt multilayer recording media. It is found that for highly exchange-coupled samples, the results from the rotational method are consistent with those from the hard-axis hysteresis loop and torque measurements. Such anisotropy measurements are applied to determine the interfacial anisotropy in Co∕Pt multilayers (MLs) by studying a series of Co∕Pt ML samples with Co thickness ranging from 0.1 to 2 nm. The Pt thickness is fixed at either 1 or 0.5 nm. It is found that the multilayer with 1 nm Pt layer shows a larger interfacial anisotropy constant (KS∼0.8erg∕cm2) than the media with 0.5 nm Pt layer (KS∼0.6erg∕cm2), corresponding to about 80% and 60% of the interfacial anisotropy of the ML made by molecular-beam epitaxy, respectively [D. Weller et al., Mater. Res. Soc. Symp. Proc. 313, 791 (1993)]. Such thickness dependence is supported by the x-ray-diffraction superlattice peak measurements that indicate the discontinuous growth for the case with thinner Pt.

Understanding how interactions within magnetic systems affect the reversal process is critical to the development of magnetic recording media. Using the first-order reversal curve (FORC) method we demonstrate an ability to map out and uniquely identify magnetic recording media. We evaluate the interactions and intrinsic switching field distribution (SFD) in single layer and exchange coupled composite granular recording media. Landau-Lifshitz-Gilbert-based simulations are used to probe the roles lateral and vertical exchange interactions have on the distribution of reversal events. We find that there is an optimal value for these terms which maximizes homogeneity of the reversal behavior.

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