High-frequency electron paramagnetic resonance investigation of the Fe3+ impurity center in polycrystalline PbTiO3 in its ferroelectric phase

The intrinsic iron(III) impurity center in polycrystalline lead titanate was investigated by means of high-frequency electron paramagnetic resonance spectroscopy in order to determine the local-environment sensitive fine-structure parameter D. At a spectrometer frequency of 190GHz, a spectral analysis of a powder sample was unambiguously possible. The observed mean value D=+35.28GHz can be rationalized if Fe3+ ions substitute for Ti4+ at the B site of the perovskite ABO3 lattice forming a directly coordinated FeTi′–VO∙∙ defect associate. A consistent fit of the multifrequency data necessitated the use of a distribution of the D values with a variance of about 1GHz. This statistical distribution of values is probably related to more distant defects and vacancies.