The effect of demagnetization fields on recording spectra

The effect of demagnetization fields on the absolute voltage wavelength response has been examined. For constant current square wave recording the data exhibits an effective spacing and record depth, both of which greatly exceed expected values. For optimum short wavelength recording (λ = 1.6μm) the effective spacings vary approximately between .5-1μm. A γFe2O3series with a 3.7:1 Mr/Hc^rvariation yielded a .25μm change in spacing. This series yielded a λ = 1.6μm output approximately independent of tape saturation remanence Mr. Measurements on higher coercivity tapes suggest a monotonic increase with remanent coercivities Hc^r. A simple model for the record process at the tape surface yields reasonable quantitative agreement with data only if the total head field gradient is utilized.