Torque magnetometry: investigation of the intergranular exchange interaction in longitudinal magnetic recording media

Abstract We demonstrate a new method for investigation of intergranular exchange coupling in longitudinal magnetic recording media by means of torque magnetometry. The technique we use is based on an analogy with the Δ M method where the analysis involves comparison of reversal processes in the sample with different initial magnetic states. We show that the Δ M curve has an equivalent torque representation Δ τ which can be similarly exploited for studies on the longitudinal media. To validate the method we involve micromagnetic modeling, results of which are compared with the experimental measurements on a model CoCrPtTa media sample.