Torsional oscillator and synchrotron x-ray experiments on solid 4He in aerogel (2008)
Mulders, N., West, J. T., Chan, M. H. W., Kodituwakku, C. N., Burns, C. A., Lurio, L. B.
X-ray diffraction experiments show that solid 4He grown in aerogel is highly polycrystalline, with a hcp crystal structure (as in bulk) and a crystallite size of approximately 100 nm. In contrast to...
X-ray Studies of Structure and Defects in Solid 4He from 50 mK to Melting (2008)
Burns, C. A., Mulders, N., Lurio, L., Chan, M. H. W., Said, A., Kodituwakku, C. N., ...
Recent measurements have found non-classical rotational inertia (NCRI) in solid 4He starting at T ~ 200 mK, leading to speculation that a supersolid state may exist in these materials. Differences in...
Thermal History of Solid 4He Under Oscillation (2007)
Clark, A. C., Maynard, J. D., Chan, M. H. W.
We have studied the thermal history of the resonant frequency of a torsional oscillator containing solid 4He. We find that the magnitude of the frequency shift that occurs below 100 mK is multivalued...
The effect of 3He impurities on the nonclassical response to oscillation of solid 4He (2007)
Kim, E., Xia, J. S., West, J. T., Lin, X., Clark, A. C., Chan, M. H. W.
We have investigated the influence of impurities on the possible supersolid transition by systematically enriching isotopically-pure 4He (< 1 ppb of 3He) with 3He. The onset of nonclassical...
Nonclassical Rotational Inertia in Single Crystal Helium (2007)
Clark, A. C., West, J. T., Chan, M. H. W.
It has been proposed that the observed nonclassical rotational inertia (NCRI) in solid helium results from the superflow of thin liquid films along interconnected grain boundaries within the sample....
Search for Superfluidity in Solid Hydrogen (2006)
Clark, A. C., Lin, X., Chan, M. H. W.
A torsional oscillator study of solid para-hydrogen has been carried out down to 20 mK in search for evidence of superfluidity. This work was inspired by the observation of the supersolid phase in...
Supersolid Helium at High Pressure (2006)
We have measured the pressure dependence of the supersolid fraction by a torsional oscillator technique. Superflow is found from 25.6 bar up to 136.9 bar. The supersolid fraction in the low...
Critical Casimir force in $^4$He films: confirmation of finite-size scaling (2006)
Ganshin, A., Scheidemantel, S., Garcia, R., Chan, M. H. W.
We present new capacitance measurements of critical Casimir force-induced thinning of $^4$He films near the superfluid/normal transition, focused on the region below $T_{\lambda}$ where the effect is...
Suppression of superconductivity in nanowires by bulk superconductors (2005)
Tian, Mingliang, Kumar, Nitesh, Xu, Shengyong, Wang, Jinguo, Kurtz, James S., Chan, M. H. W.
Transport measurements were made on a system consisting of a zinc nanowire array sandwiched between two bulk superconducting electrodes (Sn or In). It was found that the superconductivity of Zn...
Dissipation in Quasi One-Dimensional Superconducting Single-Crystal Sn Nanowires (2005)
Tian, Ming-Liang, Wang, Jin-Guo, Kurtz, James S., Liu, Ying, Mayer, Theresa S., Mallouk, Thomas E., ...
Electrical transport measurements were made on single-crystal Sn nanowires to understand the intrinsic dissipation mechanisms of a one-dimensional superconductor. While the resistance of wires of...