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

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 ($\sim 10\mu$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.

arXiv commentJ. Low Temp. Phys. in press

References in corpus (3)

• Opportunities for mesoscopics in thermometry and refrigeration: Physics and applications
• Observation of disorder-induced weakening of electron-phonon interaction in thin noble metal films
• Electron-phonon interaction in thin copper and gold films

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