Nuclear Magnetic Resonance of 51V in BiVO4 Single Crystals

Nuclear magnetic resonance spectra of 51V (I=7/2) in ferroelastic BiVO4 single crystals grown by the Czochralski method have been investigated by employing a wide-line Varian spectrometer. The seven line structure due to the quadrupole interaction was measured at a fixed frequency of 15 MHz in three mutually perpendicular crystal planes at room temperature and 77 K, well below its ferroelastic Curie temperature of 523 K. From the experimental data the quadrupole coupling constant, e2qQ/h, and asymmetry parameter, η, are determined: e2qQ/h=4.856 MHz and η=0.380 at room temperature, and 5.062 MHz and 0.459, respectively, at 77 K. The principal axes of the electric field gradient tensor are X=c, Y=a, and Z=b, where a,b, and c are crystal axes with β=90.38°. The twin structure of some of the crystals is also observed.