Effect of temperature on the luminescence of Sm3+ ions in YAM crystals

The spectroscopic features of samarium Sm3+ activated Y4Al2O9 (YAM) crystals are presented and discussed. Temperature sensing properties of Sm3+:YAM phosphor was demonstrated over the 300-1200 K range. Temperature dependent luminescence spectra and decay curves for the 4G5/2 level of Sm3+ in YAM were measured. Ratio of the fluorescence intensities arising from the two close lying 4F3/2 and 4G5/2 levels (with energy separation of ΔE ∼ 1000 cm−1) followed a straight line pattern, which confirms the Boltzmann distribution of the population, and can be used to measure temperature. The lifetime for the 4G5/2 level in 1% Sm doped sample decreases from 1.65 to 0.08 ms with heating from room temperature to 1200 K. This behavior of decays is discussed in terms of radiative and multiphonon decays as well as cross-relaxation dependence on temperature.