The effect of remanence and coercivity on short wavelength recording

Abstract

The effect of saturation remanence and coercivity on the short wavelength reproduce signal has been examined. For constant current unbiased sinewave recording on tapes of 4.5μm coating thickness, set to peak on each tape the shortest wavelength (λ=1.2μm), the data can be interpreted in terms of an effective spacing loss with an effective recording depth of 0.6μm or in terms of a loss line evaluation of the major hysteresis loop of the tapes. Within the range of remanence and coercivity under investigation, the reproduce signal can be approximated by M <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</inf> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sup> H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sup> where n and m are 0.75 and 0.25 at 23.5μm, 0.4 and 0.6 at 5μm, and 0.08 and 0.92 at 1.2μm wavelength respectively, i.e. the influence of coercivity predominates at short wavelengths.