Spin-polarized scanning electron microscopy is one of the magnetic domain observation methods. It has excellent capabilities, including high spatial resolution, high surface sensitivity, and detection of magnetization direction. Taking advantage of these capabilities, we studied the magnetism of various materials. In this paper, I select three topics from our research works, and show the results. The first is a ferromagnetism appearing at the bulk-paramagnetic material surface. The sample is FeO formed by oxidation of Fe(110). We found that the FeO surface is reconstructed (111), and ferromagnetism is localized at this surface with magnetization antiparallel to that of the underlying Fe(110). The second is an exchange coupling between ferro-and antiferromagnetic materials. Using Fe/NiO(001) we found 90
o coupling between ferromagnetic Fe spin and antiferromagnetic NiO spin, which is proposed by the theory. The third is the magnetic structure of a layered manganite of La
1.4Sr
1.6Mn
2O
7. We found that it was spatially separated into two phases: a major phase of layered antiferromagnetism and a minor phase of ferromagnetism. The spin direction of the antiferromagnetic phase area is laid down form perpendicular to parallel to the layer plane with the increase of temperature.
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