QFS2016 Book of Abstracts

Abstracts

I4.2 NMR studies of superfluid polar phase of superfluid 3 He Dmitriev V.V.(1), Soldatov A.A.(1,2), Yudin A.N.(1)

1) P.L. Kapitza Institute for Physical Problems of RAS, 119334 Moscow, Russia 2) Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia We report results of NMR experiments in superfluid polar phase of 3He. This phase is not realized in bulk 3 He, but can be stabilized in 3 He confined in a new type of aerogel (nafen) which strands are nearly parallel to one another. In our experiments the polar phase was observed in all used samples of nafen with porosities from 98% down to 77%. It was found that the region of existence of this phase essentially depends on nafen porosity, pressure and on 4 He coverage of the nafen strands. NMR properties of the polar phase and influence of spin supercurrents on the spin dynamics were investigated. Possible future experiments will be also discussed in the talk. I4.3 The A-B transition for superfluid 3 He confined to a 1.08 micrometer tall geometry Zhelev, N. (1), Abhilash, T.S.(1), Smith, E.N.(1), Bennett, R.G.(1), Rojas, X.(2), Saunders, J. (2), and Parpia, J.M. (1)* 1) Department of Physics, Cornell University, Ithaca, NY, 14853 USA 2) Department of Physics, Royal Holloway University of London, Egham, TW20 0EX Surrey, United Kingdom Motivated by recent experimental and theoretical work, we confine superfluid 3 He to a 1.08 micron thick nanofluidic cavity incorporated into the head of a torsion pendulum. For measurements between 0.1 and 5.6 bar we observe that the A phase is always interspersed between the B phase and the normal state and the superfluid fraction of the A phase is always greater than that of the B phase which is bulk-like. The dissipation is greater in the B phase than the A phase contrary to bulk behavior. Despite clean surfaces that do not pin the phase boundary, the non-monotonic supercooling of the A phase is seen to be much smaller than in the bulk. Our experiment did not observe the presence of the striped phase, likely due to bowing of the cell cavity at pressure.

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