Monitoring the Structural and Vibrational Properties in RE-Doped SrTiO₃ Ceramic Powders

X-ray diffraction and Raman spectroscopy were employed to analyze the effect of the rare earth (RE) doping (ionic radii and concentration) on the crystalline structure of Sr 0.97 RE 0.03 TiO 3 (RE = Sm 3+, Eu 3+, Gd 3+, Dy 3+, Tm 3+, Yb 3+, Lu 3+ ) and Sr 1– x Eu x TiO 3 ( x varying from 0.01 to 0.19) ceramic powders. We notice drastic changes in both structural and vibrational properties of the investigated samples for increasing dopant concentration into the SrTiO 3 (ST) lattice. The results showed evidence of RE incorporation into both A - and B -sites of the ST structure. Also, tetragonal local symmetry ( I 4/ mcm space group) was observed in RE-doped samples at room temperature from the cubic ( Pm 3̅ m ) phase exhibited by phase-pure ST ceramics. The results obtained for the Sr 1– x Eu x TiO 3 ceramic powders showed that these samples undergo a clear cubic-to-tetragonal phase transition for x ≥ 0.13 at room temperature.