Observation of Magnetic Fields in the Scanning Electron Microscope

It is shown that SEM secondary electron images and reproduced waveforms of recorded bit patterns differ for perpendicular and in-plane magnetization films. Using Co-Cr/Ni-Fe double-layer films and VTR metal tape as perpendicular and in-plane magnetization films, it was found that the magnetic flux becomes horizontal in the magnetization transition and the recording regions, respectively. It was concluded that magnetic contrast is generated in response to the magnetization transition region for Co-Cr/Ni-Fe film, and to the recording region for VTR tape. The reproduced waveforms are dependent on the horizontal component of the leakage field; the waveforms are triangular for perpendicular magnetization films, and trapezoidal for in-plane films.