交換相互作用力顕微鏡の開発と現状

概要

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Many kinds of scanning probe microscope have been proposed for imaging surface magnetic structures. Magnetic force microscope (MFM) is widely used for imaging magnetic structure. However, its spatial resolution is limited to a few tens of nanometers because the magnetic dipole interaction detected by MFM is long-range. Theoretical calculations predict that shortrange magnetic interactions such as the exchange interaction could enable non-contact atomic force microscope (NC-AFM) to image magnetic moments on an atomic scale. Recently, it was demonstrated that spinpolarized scanning tunneling microscopy (SP-STM) could image spin arrangements on an atomic scale. SP-STM requires conductive speciments, whereas NC-AFM can image even insulating surfaces such as metal oxides. Here we report atomically resolved NC-AFM measurements of the surface of an insulating antiferromagnet NiO(001) and an analysis by a superposition method. We observe two types of atoms with different corrugation amplitudes and find that their arrangement is in accord with the expected antiferromagnetic ordering. Our results demonstrate that spin-dependent interactions can be imaged in insulating samples on an atomic scale.
社団法人日本磁気学会の論文
2001-10-01