For microstructure analysis of magnetic materials, in particular, for a new class of Nd-Fe-B hard magnets, a number of magnetic imaging techniques can be applied to gain different microstructure information. For instance, SEM magnetic imaging can be successfully used for very thick samples from a bulk ones down to a sample thickness of 10-20 μ. Below this limit the resolution of SEM magnetic images generally is too low to visualize fine details of magnetic structure. For very thin samples (less then 0.5 μm) magnetic Lorentz microscopy methods in conventional TEM are very useful tools to reveal magnetic domains and their structure. Therefore, it seems that relatively thick films of 0.5-20 μm in thickness are left out of the experimental limits of the methods discussed.

We report on a novel, indirect TEM method that allows us to extend the limits of magnetic imaging for TEM non-transparent magnetic samples by viewing the surface stray fields and fringing fields generated by magnetic domains at specimen edge.