Orbital glass and spin glass states of 3He-A in aerogel
V. V. Dmitriev, D. A. Krasnikhin, N. Mulders+, A. A. Senin, G. E. Volovik*Δ, A. N. Yudin
P.L. Kapitza Institute for Physical Problems RAS, 119334 Moscow, Russia
+Department of Physics and Astronomy, University of Delaware, Newark, 19716 Delaware, USA
*Low Temperature Laboratory, Aalto University, FI-00076 AALTO, Finland
ΔL.D. Landau Institute for Theoretical Physics, 119334 Moscow, Russia
Abstract
Glass states of superfluid A-like phase of 3He in
aerogel induced by random orientations of aerogel strands are
investigated theoretically and experimentally. In anisotropic
aerogel with stretching deformation two glass phases are observed.
Both phases represent the anisotropic glass of the orbital
ferromagnetic vector - the orbital glass (OG). The
phases differ by the spin structure: the spin nematic vector can be either in the ordered spin nematic (SN) state or
in the disordered spin-glass (SG) state. The first phase (OG-SN)
is formed under conventional cooling from normal 3He. The
second phase (OG-SG) is metastable, being obtained by cooling
through the superfluid transition temperature, when large enough
resonant continuous radio-frequency excitation is applied. NMR
signature of different phases allows us to measure the parameter
of the global anisotropy of the orbital glass induced by
deformation.