Study of peak shift in thin recording surfaces

One of the most severe limitations on high-density digital recording is imposed by peak shift, which is defined as the outward displacement of the readback signal peaks corresponding to a recorded bit pattern of two successive ones followed and preceded by a number of zeros. Results of an experimental study of peak shift in thin metallic media are represented along with a correlation of the measured percent peak shift with the magnetic properties and the thickness of the media. It was found that the percent peak shift at a specified bit density varies proportionally with the thickness of the coercivity ratio for coercivities larger than 250 Oe. For lower coercivities, the remanent magnetization of the recording surface becomes increasingly significant in adversely affecting the peak shift, with a corresponding decrease in the importance of thickness. By superposing isolated pulses it was possible to predict the percent peak shift up to extremely large bit densities.