Torsional oscillator and synchrotron X-Ray experiments on solid 4He in aerogel.

Phys Rev Lett

Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA.

Published: October 2008

X-ray diffraction experiments show that solid 4He grown in aerogel is highly polycrystalline, with an hcp crystal structure (as in bulk) and a crystallite size of approximately 100 nm. In contrast to the expectation that the highly disordered solid will have a large supersolid fraction, torsional oscillator measurements show a behavior that is strikingly similar to high purity crystals grown from the superfluid phase. The low temperature supersolid fraction is only approximately 3 x 10(-4), and the onset temperature is approximately 100 mK.

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http://dx.doi.org/10.1103/PhysRevLett.101.165303DOI Listing

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