A phenomenological model for self-demagnetization in recording media

A principle is established for determining the extent of the self-demagnetized transition at equilibrium in nonsquare recording media, thereby generalizing the notion that the maximum demagnetizing field cannot exceed the coercivity. Data are presented showing that the second quadrant of the major hysteresis loop can be adequately modelled if the saturation remanence, coercivity and statistical "squareness" are known. A final arctangent distribution is phenomenologically assumed after self-demagnetization and the transition extent is found and tabulated as a function of media parameters.