Negative ion motion in normal and superfluid 3He

Abstract

We report the first measurements of negative ion motion in the superfluid phases of 3He and in the normal phase below 17 inK. Refrigeration was achieved with nuclear demagnetization of copper and we used a pulsed NMR platinum powder thermometer immersed in the liquid. In the A phase the longitudinal resonance frequency provided an additional high-resolution thermometer. In the normal phase we observed a strictly temperatureindependent mobility. In the superfluid phases we found two velocity regimes. For small applied electric fields the velocity is a linear function of the field and the corresponding mobility increases monotonically toward lower temperatures. At high electric fields the velocity is a nonlinear function of the field as a result of the pair-breaking effect of the moving ion. Available theoretical calculations are only in partial agreement with our results.

Classical mechanics at T=0: Mobility of negative ions in ^{3}He

“…We find /i agrees exactly with the well-known experimental result of Ahonen et al 5 on the mobility of negative ions in liquid 3 He.…”

Wigner Solid on the Free Surface of SuperfluidH3e

“…There are strong similarities between the WS resistance below 20 mK and the mobility of electron bubbles in liquid 3 He [17]. The inverse mobility of the bubbles is independent of temperature below 100 mK, and rapidly decreases below the superfluid transition.…”

Internal Magnus effects in superfluidA3

“…We may fix the / texture by applying an external magnetic field B, which serves to orientate the spin anisotropy axis 2 dXB; dipole interaction aligns / and d. In an experimental situation, the walls also affect / in their immediate vicinity; the resulting bulk / texture, however, lies principally in the plane perpendicular to the magnetic field. 9 It follows that the diameter of a cloud of ions moving the distance Ax, where / is oriented randomly in the plane perpendicular to the electric field, has widened by 2A>> on reaching the collector. A detectable 5° deflection would be expected already for r-0.7!T C , while for r-"0.5r c an expansion of as much as 26° is predicted.…”