Longitudinal magnetic media with soft magnetic under-layers read with magneto-resistive heads

Keepered media refers to traditional magnetic media with the addition of a soft magnetic "keeper" layer adjacent to the recording layer. Numerous recent reports have shown performance improvements associated with keepered media read with inductive heads. This report examines performance changes associated with keepered media read with magneto-resistive heads. This report presents a simple model for MR head response based on imaging, and experimental data in qualitative agreement with this model. Signal and noise spectra for keepered media are also discussed at length, and an optimized keepered media is shown to screen low spatial frequencies, narrowing isolated read pulses. Lastly, substantial noise increases at low spatial frequencies for keepered media are shown, and a possible cause is briefly discussed