Interaction of acoustic waves with nuclear spins in solids

A review of the interactions of high-frequency acoustic waves with nuclear spins in solids is presented here. These interactions result from the modulation of internal magnetic fields and electric field gradients by the impressed acoustic wave. The acoustic technique is especially useful in investigating the coupling of nuclear spins to the lattice vibrations (phonons) of the solid, and in many ways serves to complement the technique of nuclear magnetic resonance. After a qualitative introduction, the theory of nuclear spin-phonon absorption is given, both for the general case and for the special case of dynamic electric quadrupole coupling. The techniques of direct acoustic absorption and of acoustic saturation are described, and a brief summary is given of the results obtained to date.