Polarization‐resolved Raman modes of monoclinic SrAl2O4 ceramics.

Abstract

SrAl2O4 materials were obtained by molten salt synthesis and sintered at high temperatures to produce a ceramic body suitable for polarization‐resolved Raman spectroscopy measurements. Optimized experimental conditions were employed to study the complex vibrational spectrum of these ceramics under polarized light. A reliable set of experimental bands was obtained: 69 Raman modes were in fact observed, out of the 81 bands foreseen for the stable monoclinic polymorph of the material, from which 38 could be assigned as totally symmetric A‐type modes, and 31 attributed as asymmetric B‐type ones. Significant differences between experimental data and theoretical predictions indicated that additional efforts are necessary to understand these two sets of vibrational information. The knowledge of the optical phonon features reported here can help to understand the exceptional luminescence properties of SrAl2O4 in its monoclinic phase.