First direct measurement of the spin diffusion rate in a homogenous solid

The first direct measurement of the rate of spin diffusion through a homogeneous sample is reported. The measurement was performed as an incoherent scattering experiment via a combination of pulsed gradient spin echo methods with multiple pulse. pulsed gradient spatial encoding. The measurement records the destruction of a spin magnetization crating by the random translation of spin magnetization associated with the flip-flop term of the homonuclear dipole-dipole interaction. For single crystal CaF2, the measured parallel components of the spin diffusion rates are 7.1 x 10(-12) cm(2)/s along the [001] direction and 5.3 x 10(-12) cm(2)/s along the [111] direction, in good agreement with theoretical predictions.