Thermoelectric microscopy of magnetic skyrmions
The magnetic skyrmion is a nanoscale topological object characterized by the winding of the magnetic moments, appearing in magnetic materials with broken inversion symmetry. Because of its low current threshold for driving, the skyrmions have been intensely studied toward novel storage applications by using electron-beam, X-ray, and visible light microscopies. Here, we show that the skyrmions can be imaged via thermoelectric signals of spin-caloritronic phenomena in combination with focused heating. We applied a local temperature gradient to a CoFeB/Ta/W multilayer film with scanning a heating position and, by exploiting a Hall bar structure, mapped the magnitude as well as the direction of the resultant thermoelectric current distributions, which link to skyrmions' inner magnetic textures. This method also enables the observation of skyrmion dynamics under driving current pulses, being a useful imaging technique for the development of skyrmion devices.
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