Hyperfine structure of EPR spectra of Gd3+ odd isotopes in PbMoO4, Pb5Ge3O11, YVO4, and quadrupole interaction (temperature dependence)

Abstract

A hyperfine structure of EPR signals of odd isotopes Gd3+ in Pb5Ge3O11, PbMoO4, and YVO4 single crystals has been investigated at different temperatures. The observation of forbidden (with the nuclear spin flip) transitions has made it possible to determine quadrupole interaction P2 0 associated with the gradient of the electric field of ligands at the impurity. It has been shown for the first time that, under the condition pipeP2 0pipe ≥ pipeAx, ypipe (Ai are the tensor components), not only the magnitudes of splitting but also the observed asymmetry in a hyperfine structure (in perpendicular orientations of the magnetic field) depends on mutual signs of parameters of initial splitting b2 0 and P2 0. Results of studying the spectra have demonstrated that pipeb2 0(T)pipe/pipeP2 0(T)pipe ∼ const for a concrete single crystal, which assumes the similarity of physical mechanisms determining these parameters. © 2013 Pleiades Publishing, Ltd.