Metastable scheelite EuVO4 was stabilized by a high temperature and pressure method, which was transformed into a stable zircon phase by annealing treatment in air. Scheelite EuVO4 gave strong emissions with a dominant peak at 617 nm associated with the 5D0-7F2 transition of Eu3+. 151Eu Mössbauer spectra indicated that the isomer shift for the metastable scheelite phase was ca. 0.5 mm/s lower than that for the zircon phase, which was ascribed to a reduced covalency in the Eu-O bond originated via a charge transfer from oxygen to Eu3+ in scheelite lattice by producing an enhanced shielding of 4f electrons on the s orbital as well as a decrease in s electron density around Eu3+ nucleus. Impedance spectra for the zircon phase clearly demonstrated an ionic hopping in the bulk with a conductivity of ca. 1.0 × 10-3 S cm-1 at 500°C. EuVO4 is proved to be both a potential phosphor and a potential ionic conductor.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry