Nonlinear NMR in a superfluid B phase of 3He in aerogel

Abstract

The properties of liquid 3 He in a low-density aerogel preliminarily covered with a few monolayers of 4 He were studied by pulsed and nonlinear CW NMR techniques. It was found that an NMR frequency shift from the Larmor value exhibits a sharp increase at a magnetization tilting angle exceeding 104°. Nonlinear CW NMR signals related to the formation of a macroscopic region featuring homogeneous precession of the magnetization (homogeneous precession domain) were observed. The experimental results confirm that the low-temperature superfluid 3 He phase in the aerogel is analogous to the B-phase in bulk 3 He and indicate that the spin supercurrents play an important role in the spin dynamics of superfluid 3 He in aerogel.