ERASURE AND NOISE STUDY IN BARIUM-FERRITE TAPE MEDIA

Erasure and noise characteristics of longitudinally oriented Ba-ferrite tape media with different squareness values were examined. The study showed media with higher squareness values were easier to erase using longitudinal erase fields and were harder to erase using vertical erase fields than media with lower squareness values. However, at the highest squareness value, longitudinal dc fields were superior to longitudinal ac fields in erasing the signal, suggesting that there is an optimum squareness value for longitudinal ac erasure. This trend was consistent with the observed increase in positive interactions with the increasing squareness ratios. Results of the noise study showed a dip in the reverse dc demagnetization noise plot for all samples studied. Strong positive interactions caused the ac demagnetization remanence noise to reach its final level more slowly than the isothermal remanence noise. This result is in agreement with the fact that the strong positive interactions render dc fields superior to ac fields in erasing the remanent signal levels.