Measurement of internal magnetic domain structures by using backscattered electrons in a SEM

Abstract
This paper introduces a method enabling the investigation of the magnetic domain structure in the bulk of a ferromagnet utilizing the backscattered electrons of a scanning electron microscope as small electron probes to sense the internal magnetic fields. By changing the primary energy of the electron beam, different electron penetration depths can be generated. The resulting domain pictures correspond to the average magnetic field at the given electron penetration depth. By taking pictures at two different primary electron energies and subtracting them from each other, the subtracted picture contains information about the average magnetic fields in the layer between the two penetration depths.