DEFECT STRUCTURE IN "SOFT" (Gd,Fe)-CODOPED PZT 52.5/47.5 PIEZOELECTRIC CERAMIC

Ferroelectric 1 mol% Gd3+ and 0.5 mol% Fe3+ codoped "soft" Pb[Zr0.525Ti0.475]O3 ceramics were studied by means of multifrequency electron paramagnetic resonance (EPR) spectroscopy. The obtained results prove that iron is incorporated at the [Zr,Ti]-site, acting as an acceptor and building a charged (Fe'Zr,Ti - Vo°°)° defect dipole with a directly coordinated oxygen vacancy for partial charge compensation. As the La3+ ion is diamagnetic, no information is accessible about the donor. Gd3+ is an isoelectronic and paramagnetic probe for studying A-site. On the other hand, the donor forms no defect associates with lattice vacancies and rather exists as an "isolated" functional center. Consequently, also the lead vacancies that are created for charge compensation have to exist as isolated centers in compound