High-temperature relaxor ferroelectric behavior in Pr-dopedSrTiO3

Temperature-dependent Raman scattering, dielectric, and powder x-ray diffraction studies have been carried out on Pr-doped $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ ceramic samples. Activation of $\mathrm{T}{\mathrm{O}}_2$ and $\mathrm{T}{\mathrm{O}}_4$ polar modes indicated increasing degree of polar distortion by Pr doping. Dielectric measurements revealed that the system exhibits dielectric relaxation peaks at $\sim 500\mathrm{K}$. The softening tendency of the polar $\mathrm{T}{\mathrm{O}}_1$ soft mode decreases with increasing Pr doping. X-ray diffraction results show no evidence of symmetry breaking across the dielectric peak temperatures. The system exhibits features of high-temperature relaxor ferroelectrics.