Magnetic Domain Imaging of Nd2Fe14B Single Crystals With Unmodified Scanning Electron Microscopy

The stray flux manifestations of surface magnetic domains found in as-grown Nd2Fe14B single crystals were observed by conventional scanning electron microscopy (SEM) without instrumental modifications. Kerr optical microscopy was employed to confirm the results obtained by SEM. Spike domains were observed on the (001) plane, while a lozenge-type domain pattern was observed on (223) plane of Nd2Fe14B. A modified image-distortion mode was applied to image the three-dimensional stray flux emanating from the sample. The optimum scanning electron microscope imaging conditions are attained with an incident-electron energy set at 5 to 6kV, which produced images with resolution on the order of 1μm. The simplicity of the technique and the ready adaptability of the SEM to such modifications as in situ current and magnetic field application suggest the extension of these to investigations of other materials of technological interest, such as perpendicular media disks.