Sp. Alpay et al., Effect of the electrode layer on the polydomain structure of epitaxial PbZr0.2Ti0.8O3 thin films, J APPL PHYS, 85(6), 1999, pp. 3271-3277
PbZr0.2Ti0.8O3(PZT) thin films with and without La0.5Sr0.5CoO3(LSCO) electr
odes were grown epitaxially on (001) SrTiO3 at 650 degrees C by pulsed lase
r deposition. The domain structure of the 400 nm thick PZT films with diffe
rent electrode layer configurations was investigated by x-ray diffraction a
nd transmission electron microscopy. The c-domain fractions of the PZT film
s with no electrode layer, with a 50 nm electrode layer between the film an
d the substrate, and with 50 nm electrode layers on top and bottom of the P
ZT film were found to be equal. Theoretical estimation of the c-domain frac
tion based on the minimization of the energy of internal stresses in films
is in good agreement with experimental results. This means that depolarizin
g fields do not affect the polydomain structure of the film. Calculations o
f the in-plane strains based on the lattice parameters of the LSCO layer in
the above configurations led to the conclusion that the bottom electrode l
ayer is coherently strained to match the substrate. (C) 1999 American Insti
tute of Physics.