Effect of dipolar fields in highly magnetized samples of liquid 3He-4He mixtures

NMR free induction decay signals obtained in highly polarized liquid 3He-4He mixtures in a U-shaped cell and in a coil-shaped cell significantly differ from the signal one would obtain from independently precessing spins. We have analyzed the spin dynamics using two different models. Both consider the precession of the local magnetization in the dipolar field produced by the remainder of the sample. The first model explains the observed phenomena qualitatively; the second, solved numerically reproduces satisfactorily the structure of experimental spectra