Electron Energy Loss Spectra of Rare Earth Vanadates: RVO4 (R=Sc, Y, La, Eu and Gd)

Abstract

Electron energy-loss spectra of RVO 4 ( R =Sc, Y, La, Eu and Gd) are measured to elucidate primary excitation processes in cathodoluminescence. To help assign loss spectra, calculation of optical constants and measurement of X-ray photo-electron spectra are also made. The loss spectra show seven or eight peaks with four different types of origins: (1) internal transitions, in the VO 3- 4 complex observed as small peaks below 10 eV, (2) plasmon excitation inducing the largest peak at 13 to 14 eV, (3) excitation of a core p-electron of R-ions giving rise to another large peak at 28 to 40 eV and (4) excitation of a V 3p-electron observed as a small peak at 47 to 51 eV. Thus, the importance of core-electron excitation in cathode-ray excitation is emphasized.