Abstract
Hotspots generated in a thin-film superconductor through dissipation of Joule energy are imaged by scanning the sample with the electron beam of a scanning electron microscope equipped with a liquid He stage. The signal utilized for imaging is the change of the sample voltage caused by the beam irradiation. A theoretical analysis of the heat balance equation indicates that the voltage signal reaches a maximum at the hotspot boundaries where the temperature profile passes through the critical temperature value of the superconductor. The predictions of our theoretical model agree well with our experiments performed using films of pure Sn, O2-doped Sn, and O2-doped Al. The width of the signal peaks marking the hotspot boundaries is twice the thermal healing length of the film/substrate configuration.
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Supported by a grant from the Deutsche Forschungsgemeinschaft, by the Director for Energy Research, Office of Basic Energy Sciences, and by the NATO Research Grants Program.
Operated for the U.S. Department of Energy by Iowa State University under contract No. W-7405-Eng-82.
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Eichele, R., Freytag, L., Seifert, H. et al. Two-dimensional imaging of hotspots in superconducting bridges by low-temperature scanning electron microscopy. J Low Temp Phys 52, 449–479 (1983). https://doi.org/10.1007/BF00682126
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DOI: https://doi.org/10.1007/BF00682126