Influence of exchange on signal-to-noise ratio in longitudinal recording media

Abstract

In this work a systematic study of the influence of exchange on media signal-to-noise ratio, (SNR) was undertaken. Log-normal grain distributions were utilized and four models of the intergranular exchange interaction were studied. In addition, three models of media SNR were examined. In all of our studies media SNR was found to plateau and then exhibit a small maximum as exchange is increased. This maximum occurs because remanent magnetization at the center of the bit increases faster than the noise grows at the bit transition in this low coupling regime. For larger values of exchange, the signal-to-noise ratio decreases due to the rapid increase of transition noise. These results suggest that this plateau region should be exploited in studies of the effect of exchange on thermal stability. © 2002 American Institute of Physics.