Effects of playback on saturation remanent state noise

DC modulation noise as a function of number of replay passes has been inves tigated for a number of systems including CrO2, cobalt modified gamma-Fe2O3 , barium ferrite and metal particle tapes. In CrO2 and cobalt modified gamm a-Fe2O3, within the frequency band of 2-10 kHz, noise was observed to incre ase with number of passes and the effect was attributed to inverse magnetos triction effects within the magnetic layer of the recording media. This has been related to signal loss observed in some early recording tapes contain ing acicular ferrite particles. Measurements have so far failed to detect n oise increases in samples of barium ferrite and metal particles. Experiment s to investigate the relationship between noise and number of passes, the d ependence on applied stress and initial conditions are described. (C) 1999 Elsevier Science B.V. All rights reserved.