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

TL;DR

This study uses high-frequency EPR spectroscopy to analyze Fe3+ impurities in polycrystalline PbTiO3, revealing local environment details and defect associations in the ferroelectric phase.

Contribution

It provides detailed high-frequency EPR analysis of Fe3+ in PbTiO3, identifying the local environment and defect structures with unprecedented spectral clarity.

Findings

Fe3+ substitutes Ti4+ at B-site in PbTiO3

Observed D value of +35.28 GHz indicates local environment

Distribution of D values suggests presence of distant defects

Abstract

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