Comparison of calculated and actual density responses of a magnetoresistive head

Using a shielded MR read head, we have successfully recorded and reproduced an all-ones pattern at data densities up to 5600 flux charges/mm (fc/mm). Both NRZ and AC bias waveforms were used in the write element. No indication of the gap null expected at 4000 fc/mm was seen. An analytic expression for the response of a shielded magnetoresistive head with the element located assymmetrically in the gap to a sinusoidal magnetization pattern has been developed. This expression fits the observed density response quite well.