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Sub-100 mK cooling using normal-metal¿insulator¿superconductor tunnel junctions



Peter J. Lowell, Galen C. O'Neil, Jason M. Underwood, Xiaohang NMN Zhang, Joel N. Ullom


Normal-metal∖insulator∖superconductor (NIS) junctions can be used as solid-state refrigerators since the hottest electrons preferentially tunnel from the normal metal into the superconductor. In this paper, we present NIS junctions optimized to cool electrons from a bath temperature of 100 mK. We measure a temperature reduction of the electrons in the refrigerator junctions from 100 to 26 mK which agrees with device models. Independent measurements of the electron temperature using thermometer junctions measure a temperature decrease from 100 to 48 mK. Theories explaining the difference in measured temperatures are discussed.
Journal of Low Temperature Physics


Microrefrigerators, Superconducting tunnel junctions


Lowell, P. , O'Neil, G. , Underwood, J. , , X. and Ullom, J. (2013), Sub-100 mK cooling using normal-metal¿insulator¿superconductor tunnel junctions, Journal of Low Temperature Physics, [online], (Accessed June 17, 2024)


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Created December 15, 2013, Updated November 10, 2018