Nuclear magnetic resonance of atomic motions in vanadium

Atomic motions in solid vanadium have been investigated by means of NMR. For that purpose, the Zeeman spin-lattice relaxation time, the rotating-frame spin-lattice relaxation time, and the Knight shift of V in polycrystalline vanadium have been measured as a function of temperature in the range between 300 and 2000 K. At all temperatures, the relaxation time is mainly determined by electronic contributions leading to a temperature-dependent expression. In contrast to the data, two pronounced peaks in the relaxation rate at about 750 and 1600 K, respectively, are observed. The peak at 750 K arises from fluctuations in the nuclear quadrupolar interaction between vanadium and interstitially migrating oxygen whereas the maximum at 1600 K is caused by fluctuation in the nuclear dipole interaction due to atomic self-diffusion. From the low-temperature data, the diffusivity of oxygen is determined.