Multifrequency electron paramagnetic resonance analysis of polycrystalline gadolinium-doped PbTiO3—Charge compensation and site of incorporation

Gadolinium(III)-modified polycrystalline lead titanate (PbTiO3) of 1.0mol% dopant level was investigated by means of multifrequency electron paramagnetic resonance spectroscopy in order to determine sign and size of the local-environment sensitive finestructure parameter B20. The Gd3+ ions were assigned to substitute for Pb2+ at the A site of the perovskite ABO3 lattice, providing donor centers. The obtained value amounts to B20=0.776(2)GHz at ambient temperature and 0.860(2)GHz at 5K, thus showing a considerable temperature dependence. A charge-compensation mechanism is proposed that is based solely on the creation of lead and oxygen vacancies.