Optical spectrum of Mn4+ in Y2Ti2-xSnxO7 pyrochlore solid solution: R-line energy and intensity

Abstract In this work, we investigated the luminescence of the Mn4+ ions in Y2Ti2-xSnxO7 (x = 0, 0.5, 1.0, 2.0) pyrochlore solid solutions and compared the results with the spectroscopic data of the two end members. The emission spectra in the mixed pyrochlore solid solutions are broadened relative to the end members due to long range disorder between the Sn4+ and Ti4+ ions. The R-line intensity is particularly weak in both Y2Sn2O7 and Y2Ti2O7. The increase in R-line intensity in the mixed pyrochlore solid solutions is attributed to the random distribution of Sn4+ and Ti4+ ions in the second coordination sphere (next nearest neighbors) that removes the inversion symmetry about the Mn4+ ion. We find a linear relation between the energy position of the R-line and x in Y2Ti2-x SnxO7 (2Eg (cm−1) = 15 010 + 163.0 x; R2 = 0.98).