Measurements of spin diffusion in liquid³He in “ordered” aerogel

Abstract

We report measurements of spin diffusion in normal phase of liquid 3He confined to "ordered" aerogel. This aerogel consists of Al2O3·H2O strands which are nearly parallel to each other at macroscopic distances. At low temperatures strong anisotropy of such aerogel may be detected as anisotropy of 3He spin diffusion. Experiments were done at pressure of 2.4 bar using spin echo techniques for two orientations of magnetic field gradient (parallel and normal to the strands). Values of spin diffusion for these two directions of the gradient were found to be different at temperatures below ∼20mK. In zero temperature limit the ratio of obtained principal values of the spin diffusion tensor is about 2.