1111.1972 (L. Casparis et al.)

Metallic Coulomb Blockade Thermometry down to 10 mK and below    [PDF]

L. Casparis, M. Meschke, D. Maradan, A. C. Clark, C. Scheller, K. K. Schwarzwalder, J. P. Pekola, D. M. Zumbuhl

Using a recently developed demagnetization refrigerator aimed at microkelvin
nanoelectronic experiments, we investigate metallic Coulomb blockade
thermometers (CBTs) with various tunnel-junction resistances Rj. The
refrigerator cools as low as 0.3 mK while the CBTs saturate at ~10 mK,
consistent with weak electron-phonon coupling for the high-Rj sensor and a
residual heat leak of 40 aW. More efficient Wiedemann-Franz cooling contributes
noticeably for lower-Rj junctions, though these CBTs appear to be more
susceptible to environmental heating. Finally, we discuss possible improvements
for cooling nanosamples well below 10 mK.

View original: http://arxiv.org/abs/1111.1972