Oxygen vacancy kinetics in ferroelectric PbZr0.4Ti0.6O3 were studied by 18O tracer

self-diffusion in epitaxial thin films as well as bulk polycrystalline samples. The

18O exchange annealing was carried out at an oxygen partial pressure of 250mbar

and 250 to 400C. Isotope depth profiling was performed by secondary ion mass

spectrometry as well as neutral secondary mass spectrometry. The observed

concentration depth profiles of the polycrystalline samples showed two distinct

diffusion paths, namely, bulk diffusion and grain boundary diffusion. It appeared to

be of type B-kinetics in the investigated temperature range, with DGB/Dbulk >> 100.

Donor doped samples with different levels of Nb5+ (1 to 4mol%) were also

investigated. The effect on the diffusion depth profiles, however, were negligible

and can solely be attributed due to the change in the samples microstructure as

induced by the dopants. The diffusion coefficient for the bulk diffusion of 18O was

given by,

D (cm2/s) = 1 x 10−7exp[−0.87(eV)/kT]

The faster grain boundary diffusion process involved an activation enthalpy of only

0.66eV.

Oxygen Vacancy Kinetics in Ferroelectric PbZr0.4Ti0.6O3. S.Gottschalk, H.Hahn,

S.Flege, A.G.Balogh: Journal of Applied Physics, 2008, 104[11], 114106