A microkelvin cryogen-free experimental platform with integrated noise thermometry

We report experimental demonstration of the feasibility of reaching temperatures below 1mK using cryogen-free technology. Our prototype system comprises an adiabatic nuclear demagnetization stage, based on hyperfineenhanced nuclear magnetic cooling, integrated with a commercial cryogenfree dilution refrigerator and 8 T superconducting magnet. Thermometry was provided by a current-sensing noise thermometer. The minimum temperature achieved at the experimental platform was 600μK. The platform remained below 1mK for over 24 h, indicating a total residual heat-leak into the experimental stage of 5 nW. We discuss straightforward improvements to the design of the current prototype that are expected to lead to enhanced performance. This opens the way to widening the accessibility of temperatures in the microkelvin regime, of potential importance in the application of strongly correlated electron states in nanodevices to quantum computing. 3 Authors to whom any correspondence should be addressed. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. New Journal of Physics 15 (2013) 113034 1367-2630/13/113034+11$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft