We present results of a Au-Ge alloy that is useful as a resistance-based thermometer from room temperature down to at least \SI{0.2}{\kelvin}. Over a wide range, the electrical resistivity of the alloy shows a logarithmic temperature dependence, which simultaneously retains the sensitivity required for practical thermometry while also maintaining a relatively modest and easily-measurable value of resistivity. We characterize the sensitivity of the alloy as a possible thermometer and show that it compares favorably to commercially-available temperature sensors. We experimentally identify that the characteristic logarithmic temperature dependence of the alloy stems from Kondo-like behavior induced by the specific heat treatment it undergoes.
@article{arxiv.1902.10111,
title = {Au-Ge alloys for wide-range low-temperature on-chip thermometry},
author = {J. R. A. Dann and P. C. Verpoort and J. Ferreira de Oliveira and S. E. Rowley and C. J. B. Ford and G. J. Conduit and V. Narayan},
journal= {arXiv preprint arXiv:1902.10111},
year = {2019}
}