Characterization of (Fe Zr,Ti -V o ldrldr ) ldr defect dipoles in (La,Fe)-codoped PZT 52.5/47.5 piezoelectric ceramics by multifrequency electron paramagnetic resonance spectroscopy

Ferroelectric 1 mol.% La 3+ and 0.5 mol.% Fe 3+ codoped Pb[Zr 0.54 Ti 0.46 ]O 3 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 - V o ldrldr ) ldr defect dipole with a directly coordinated oxygen vacancy for partial charge compensation. This feature of the defect associates has hitherto been identified only in hard, exclusively Fe 3+ -doped PZT compounds. The present results show, however, that a similar defect association of the Fe 3+ functional center with a V o ldrldr also exists in soft, donor-acceptor (La 3+ ,Fe 3+ )-codoped PZT. According to models developed by Arlt et al. electric dipoles from defect associates, such as the (Fe Zr,Ti - V o ldrldr ) ldr defect associate, which may give rise to an internal bias field that is discussed being responsible for ferroelectric aging.