Self-consistent approximations in the theory of triplet pairing superfluidity in3He

Spin-lattice relaxation times of bcc solid ³ He with impurity concentrationsx of ⁴ He, 1.4×10 ^?3 <x<7 × 10 ^?3 , have been studied by NMR pulse techniques in the temperature range 0.27 K<T<1.2 K. In the lower part of the temperature range a temperature-independent relaxation process governed by the impurities is observed and its characteristic timeT _1D varies as a simple function ofx:T _1D> ∞x ^?3; the features of this process seem to be consistent with a diffusion mechanism to some clusters of ⁴ He impurities. In this plateau region a long relaxation time is also measured and found to be insensitive tox and strongly dependent on the temperature. A phenomenological model is suggested.