Far infrared study of impurity local modes in Pr doped PbTe

Single crystal samples of lead telluride doped with Pr were produced using the Bridgman method. Far infrared spectra of the samples doped with 0.15 at%, 0.25 at% and 0.6 at% Pr are presented. The experimental data were numerically analyzed using a fitting procedure based on the plasmon-phonon interaction model and optical parameters were determined. Two local modes of praseodium were observed at about 158 cm(-1) and 257 cm(-1) at room temperature. The origin of the local modes was discussed