title: Torsional oscillator and synchrotron X-Ray experiments on solid 4He in aerogel.
abstract: 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.
authors.affiliation: Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA.
authors.forename: N
authors.initials: N
authors.lastname: Mulders
authors.forename: J T
authors.initials: JT
authors.lastname: West
authors.forename: M H W
authors.initials: MH
authors.lastname: Chan
authors.forename: C N
authors.initials: CN
authors.lastname: Kodituwakku
authors.forename: C A
authors.initials: CA
authors.lastname: Burns
authors.forename: L B
authors.initials: LB
authors.lastname: Lurio