Spectral hole burning and optically detected nuclear quadrupole resonance in flux-grown stoichiometric europium vanadate crystals

Abstract

Earlier work [Cone {ital et al.}, J. Phys. C {bold 17}, 3101 (1984); Cone {ital et al.}, J. Phys.: Condens. Matter {bold 5}, 573 (1993)] on EuVO{sub 4} has described the fluorescence excitation spectra associated with the large number of defect sites ({gt}50) previously discovered in this material. To establish which if any of the defect sites were intrinsic to the EuVO{sub 4} crystal structure rather than being dependent on particular growth procedures, EuVO{sub 4} crystals were prepared from fluxes with different compositions. The present work extends this study, using the techniques of spectral hole burning and optical detection of nuclear quadrupole resonance to examine at much higher precision the degree to which the defect spectra associated with the various crystal growths are identical, and to attempt a preliminary correlation of such spectra with the methods of crystal growth. We discuss the relative importance of the lattice and electronic contributions to the ground-state quadrupole interactions and conclude that the electronic contribution is almost always larger than the lattice contribution. The data also allow conclusions to be drawn regarding the relative importance of {ital pseudoquadrupolar} effects in the spectra and they are found to be small. This work forms a basismore » for detailed study of particular defect sites to be discussed in further papers. {copyright} {ital 1997} {ital The American Physical Society}« less