| Nuclear Magnetic Resonance (NMR) normally requires relatively large samples for adequate signal-to-noise. NMR spectroscopists often go to great lengths to achieve signal enhancements of only 2 . However, sensitivity can be greatly improved in some materials by transferring nuclear polarization from hyperpolarized 129Xe. Indeed, enhancements by factors of ∼200 have already been achieved. The methods that will be described include the production of hyperpolarized 129Xe and signal enhancement of 13C by Hartmann-Hahn polarization transfer and low-field thermal mixing.; In addition, relaxation studies of the intermetallic ZrNiH x and ZrNiDx were performed using hydrogen and deuterium NMR. Correlation times for atomic diffusion were determined based on the temperature dependence of spin-lattice and spin-spin relaxation times. The motion is shown to be thermally activated over the temperature range 200--575 K and the activation energies for diffusion are determined. The deuterium NMR, spectra exhibit comparatively little line narrowing with temperature, indicating that the average electric field gradient is not zero, averaged over the deuterium atom sites of these non-cubic; cells. Furthermore, the spectrum of ZrNiD1.87 reveals a coexistence of two phases, in agreement with the phase diagram. |
