High-resolution field measurements near ferrite and thin-film recording heads

The accuracy of high-resolution magnetic field measurements near ferrite heads was increased by using an improved interference method for determining the measurement height, by measuring a known field distribution to calibrate the system, and by using a more accurate theory to compare with the data. Measurements on three MnZn heads gave dead-layer thicknesses of 0,0, 0.01 and 0.07 μm, which are practically negligible. Measurements near thin-film heads gave a gap-field distribution in good agreement with the theory of Potter et al, and showed no degradation of resolution after head saturation. Poor resolution was observed at the track edge for thin-film heads when the top and bottom poles were of unequal width.