He-a in Aerogel
نویسنده
چکیده
Glass states formed in the superfluid 3 He confined in aerogel are discussed. If the short range order corresponds to the A-phase state, the glass state is nonsuperfluid in the long wave length limit. The superfluidity can be restored by application of a small mass current. Transitions between the superfluid and nonsuperfluid glass states can be triggered by small magnetic field and by the change of the tipping angle of magnetization in NMR experiments.
منابع مشابه
Aerogel Growth, Optical Birefringence Characterization, and Use in Ultra Low Temperature Superfluid
Superfluid He has important implications in studying condensed matter physics, specifically in its phases at very low temperatures. The understanding of these phases not only expands our knowledge of He itself, but is also a paradigm for recently discovered unconventional superconductors such as strontium ruthenate (SrRuO3) and uranium platinum three (UPt3). Superfluid He’s relation to supercon...
متن کاملSuperfluid Phase Stability of He in Axially Anisotropic Aerogel
Measurements of superfluid He in 98% aerogel demonstrate the existence of a metastable A-like phase and a stable B-like phase. It has been suggested that the relative stability of these two phases is controlled by anisotropic quasiparticle scattering in the aerogel. Anisotropic scattering produced by axial compression of the aerogel has been predicted to stabilize the axial state of superfluid ...
متن کاملMagnetic Susceptibility of the Balian-Werthamer Phase of He in Aerogel
The equilibrium superfluid phase of He impregnated into high-porosity silica aerogels appears to be a non-equal-spin-pairing state in zero field at all pressures, which is generally assumed to be the Balian-Werthamer (BW) phase modified by the depairing effects of the aerogel structure. The nuclear magnetic susceptibility played a key role in identifying the B-phase of pure He with the BW state...
متن کاملElementary excitations of liquid He in aerogel
The phonon-roton excitations of liquid He immersed in aerogel of 95% porosity have been measured using inelastic neutron scattering. Excitations having wave vectors at the phonon (Q50.2 Å ), maxon, roton, and beyond the roton (Q52.4 Å ) regions of the dispersion curve were investigated at temperatures between T50.5 K and T52.25 K. Aerogel grown with deuterated materials not exposed to air was u...
متن کاملCorrelated disorder in a p-wave superfluid
The role of aerogel as a means of introducing correlated disorder into superfluid He is examined in this paper. The aerogel structure is described by a diffusion-limited cluster aggregation model and compared to the results of small-angle x-ray scattering obtained from samples that were used to study the suppression of Tc as well as the development of the superfluid fraction. These results high...
متن کاملAcoustic Spectroscopy of Superfluid He in Aerogel
We have designed an experiment to study the role of global anisotropic quasiparticle scattering on the dirty aerogel superfluid He system. We observe significant regions of two stable phases at temperatures below the superfluid transition at a pressure of 25 bar for a 98% aerogel.
متن کامل