Magnetic domain contrast in backscattered electron images obtained with a scanning electron microscope

Abstract

Magnetic domain contrast in backscattered electron images of an iron-3% silicon specimen has been measured at 50–200 kV by using a high-voltage scanning electron microscope, and a detailed study has been made of the dependence of the contrast on detection direction and accelerating voltage. The contrast is maximum at a take-off angle of about 60° for both 45° and 60° specimen tilts. The contrast is approximately proportional to the 3/2 power of the accelerating voltage, as shown by Newbury, Yakowitz and Myklebust (1973) and by Fathers, Jakubovics, Joy, Newbury and Yakowitz (1973 b, 1974). The resolution of domain images and the material depth effective for the magnetic contrast have been studied. They are also dependent on the detection direction: the resolution is high and the depth is small at a lower take-off angle than that corresponding to the mirror-symmetrical direction, whereas they are low and large, respectively, at a higher take-off angle. The contrast mechanism is also discussed on the basis of Monte Carlo calculation data.