Key points are not available for this paper at this time.
The scanning electron microscope has been used to obtain quantitative values for the fields and field gradients emerging from magnetic heads or tapes. The microscope is used to image a known reference detail adjacent to the field source and the fields are computed from the resultant pattern distortion. Gradients are obtained by measuring the resultant astigmatism of the scanning beam. Fields down to 10 Oe were measured from a tape recorded at 100 cycles/cm.
Thornley et al. (1968) studied this question.