Solid solutions and crystal fields in (La1-xYx)OBr:Eu3+

Abstract The formation of solid solutions in the (La1-xYx)OBr (0 ⩽ × ⩾ 1) series has been studied by X-ray powder diffraction (XRD) and by ultraviolet excited luminescence spectroscopy. The 5D0→7F0–4 and 5D1→7F3 emission spectra of the Eu3+ ion are interpreted according to the C4v point symmetry of the RE3+ site (RE ≡ rare earth) in REOBr. The 7F0–4 level schemes are consequently simulated by a phenomen-ological crystal-field (CF) theory to yield a quantitative measure of the formation of the solid solutions. The XRD analyses revealed the separation of different REOBr phases, but neither the coexistence of phases in the middle of the (La1-xYx)OBr series nor the composition of these phases could be disclosed. The separation of phases in both ends of the series, the existence of both the lanthanum-rich and yttrium-rich phases as well as the composition of the solid solutions could be determined by the photoluminescence spectroscopy. The CF analysis gave in each case satisfactory results with r.m.s. deviatio...