Orbital Glass and Spin Glass States of 3He-A in Aerogel

Glass states of superfluid A-like phase of He-3 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 (I) over cap -the orbital glass (OG). The phases differ by the spin structure: the spin nematic vector (d) over cap 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 He-3. 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. DOI: 10.1134/S0021364010110123