Nuclear magnetic resonance in LiF: a single nuclear-dipolar-spin temperature in crystals with more than one spin species

In a crystal containing more than one species of nuclear spin in a large dc magnetic field, the secular dipolar interactions between all spins, unlike as well as like, form a single reservoir described by a single spin temperature. We demonstrated this concept with experiments on LiF. In particular, we showed that TXD of 7Li and 1 9F are equal. We also measured TX and TXP of 1 9F using 7Li detection. Finally we applied this concept'to the Provotorov theory of saturation, which we extended to the case of a two-spin system, and demonstrated experimentally the validity of the treatment.