Electron Paramagnetic Resonance ofYb3+in Scheelite Single Crystals

Abstract

The electron paramagnetic resonance spectra of the ground state of trivalent ytterbium have been observed in eight single crystals with scheelite structure at 4.2°K and $X$ band frequencies. The crystals used were CdMo${\mathrm{O}}_4$, CaW${\mathrm{O}}_4$, CaMo${\mathrm{O}}_4$, SrW${\mathrm{O}}_4$, SrMo${\mathrm{O}}_4$, PbW${\mathrm{O}}_4$, PbMo${\mathrm{O}}_4$, and BaW${\mathrm{O}}_4$. The tetragonal spectra for ${\mathrm{Yb}}^{171}$, ${\mathrm{Yb}}^{173}$, and the even isotopes of ytterbium were best fitted with an axial spin Hamiltonian. The $g$ factors were found to have a linear dependence on the crystal $c$-axis lattice constant. All ground-state wave functions were found to be ${\Gamma }_{5,6}$. The values of $〈{\mathcal{r}}^{-3\mathrm{}}〉$ were calculated for ${\mathrm{Yb}}^{3+}$ in each of the crystals, and all were found to have the value $〈{\mathcal{r}}^{-3\mathrm{}}〉=12.5\mathrm{}$ a.u. Inclusion of an orbital reduction factor correction changes this value to $〈{\mathcal{r}}^{-3\mathrm{}}〉=12.8\mathrm{}$ a.u.