Nuclear magnetic resonance of²⁰⁹Bi in a BiVO₄single crystal

Abstract

Nuclear magnetic resonance spectra of 209Bi(I=9/2) in the ferroelastic BiVO4 single crystal has been investigated by employing a wide-line Varian spectrometer. Only three lines due to a large quadrupole interaction were measured at a fixed frequency of 6 MHz in the principal planes at room temperature. From the experimental data the quadrupole coupling constant E2qQ/h=79.2+or-0.1 MHz and asymmetry parameter eta =0.70+or-0.01 are determined; however, these values turn out to be quite different from the previous report obtained with a ceramic sample at liquid-nitrogen temperature. The principal axes of the electric field gradient tensor are determined for the first time, the x, y and z axes being the crystallographic c+25 degrees , a+25 degrees , and b axes, respectively. Thes directions are discussed in terms of the Bi-O bonds in the Bi-O polyhedra.