Microstructuring YbRh2Si2 for resistance and noise measurements down to ultra-low temperatures
MetadataShow full item record
Altmetrics Handle Statistics
Altmetrics DOI Statistics
The discovery of superconductivity in the quantum critical Kondo-lattice system YbRh2Si2 at an extremely low temperature of 2 mK has inspired efforts to perform high-resolution electrical resistivity measurements down to this temperature range in highly conductive materials. Here we show that control over the sample geometry by microstructuring using focused-ion-beam techniques allows to reach ultra-low temperatures and increase signal-to-noise ratios (SNRs) tenfold, without adverse effects to sample quality. In five experiments we show four-terminal sensing resistance and magnetoresistance measurements which exhibit sharp phase transitions at the Néel temperature, and Shubnikov–de-Haas (SdH) oscillations between 13 T and 18 T where we identified a new SdH frequency of 0.39 kT. The increased SNR allowed resistance fluctuation (noise) spectroscopy that would not be possible for bulk crystals, and confirmed intrinsic 1/f -type fluctuations. Under controlled strain, two thin microstructured samples exhibited a large increase of TN from 67 mK up to 188 mK while still showing clear signatures of the phase transition and SdH oscillations. Superconducting quantum interference device-based thermal noise spectroscopy measurements in a nuclear demagnetization refrigerator down to 0.95 mK, show a sharp superconducting transition at Tc=1.2 mK. These experiments demonstrate microstructuring as a powerful tool to investigate the resistance and the noise spectrum of highly conductive correlated metals over wide temperature ranges.
Steppke , A , Hamann , S , König , M , Mackenzie , A P , Kliemt , K , Krellner , C , Kopp , M , Lonsky , M , Müller , J , Levitin , L V , Saunders , J & Brando , M 2022 , ' Microstructuring YbRh 2 Si 2 for resistance and noise measurements down to ultra-low temperatures ' , New Journal of Physics , vol. 24 , no. 12 , 123033 . https://doi.org/10.1088/1367-2630/aca8c6
New Journal of Physics
Copyright © 2022 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft. Original Content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
DescriptionFunding: We acknowledge funding by the German Research Foundation (DFG) via the TRR 288 (422213477, project A03, A10 and B02) and projects KR3831/4-1 and BR 4110/1-1. This work was supported by the EU H2020 European Microkelvin Platform EMP, Grant No. 824109.
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.