Spin-wave modes and spin diffusion anisotropy in a He-3-He-4 mixture at high B/T

We present nmr measurements in a 6.2% He-3-He-4 mixture carried out at 11.3 T with temperatures dow to 3.5 mK, yielding a very high B/T ratio. We have measured the transverse spin diffusion with the spin-echo technique. We ob serve a saturation of the spin diffusion coefficient at low temperature cor responding to an anisotropy temperature T-alpha similar or equal to 13mK. U sing the same set-up, we were able to excite Silin spin-wave modes in the e xperimental cell.