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

Abstract

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 $T_{1D}$ of ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ are equal. We also measured $T_1$ and $T_{1\rho }$ of ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ using ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ 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.