Concentration-dependent site occupancy in europium-doped Y2WO6 as studied by 151Eu Mössbauer spectroscopy

151 Eu Mössbauer spectroscopy is used to investigate the phosphor Y 2− x Eu x WO 6 . The interpretation of the spectra is based on the existence of three non-equivalent yttrium sites on which Eu can be substituted. Small differences in the covalency for the three sites can explain the different isomer shifts. It is shown that the relative occupancy of one of the sites strongly depends of the europium content.