Optical evidence of the zircon-type lanthanum orthovanadate

Summary The fluorescence spectra of the trivalent europium ion embedded in lanthanum orthovanadate in polycrystalline form reveal the existence of LaVO 4 in its tetragonal form, i.e. having the zircon type structure. The lattice parameters of Eu 3+ 10%: LaVO 4 follow the linear variation vs the ionic radius in the rare earth series. The variation of the 7 F 1 crystal field levels is connected to the crystal Field (cf) parameter B 0 2 , whose sign changes for LaVO 4 : Eu 3+ . This feature suggests a method for characterizing a structural change of an isostructural series and for detecting the existence limit of the phase.