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Influence of temperature gradients on tunnel junction thermometry below 1 K: cooling and electron-phonon coupling

J. T. Karvonen·L. J. Taskinen·I. J. Maasilta
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Abstract

We have studied thermal gradients in thin Cu and AlMn wires, both experimentally and theoretically. In the experiments, the wires were Joule heated non-uniformly at sub-Kelvin temperatures, and the resulting temperature gradients were measured using normal metal-insulator-superconducting tunnel junctions. The data clearly shows that even in reasonably well conducting thin wires with a short ($\sim 10 μ$m) non-heated portion, significant temperature differences can form. In most cases, the measurements agree well with a model which includes electron-phonon interaction and electronic thermal conductivity by the Wiedemann-Franz law.

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J. T. Karvonen, L. J. Taskinen, I. J. Maasilta. 2006-12-19. Influence of temperature gradients on tunnel junction thermometry below 1 K: cooling and electron-phonon coupling. https://doi.org/10.1007/s10909-006-9264-y

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