A contribution to anhysteretic remanence and AC bias recording

It is shown that the anhysteretic remanent magnetization (ARM) of magnetic tapes as a function of field strength can be represented by an universal curve in a coordinate system whose ordinate is ARM divided by the ARM saturation value and whose abscissa is the field divided by the value necessary to produce an ARM which is equal to one half of ARM-saturation. A corresponding relationship is shown to hold for actual ac bias analog recording. From the non linear characteristic of ARM the third harmonic distortion, k3, in analog recording is calculated and compared with experiment. It is concluded and verified experimentally that for magnetic coatings with thickness comparable to the write head gap length the signal at constant k3is proportional to the remanent saturation flux-of the coating.