F. Wang et S. Leppavuori, PROPERTIES OF EPITAXIAL FERROELECTRIC PBZR0.56TI0.44O3 HETEROSTRUCTURES WITH LA0.5SR0.5COO3 METALLIC OXIDE ELECTRODES, Journal of applied physics, 82(3), 1997, pp. 1293-1298
PbZr0.56Ti0.44O3 (PZT) epitaxial ferroelectric thin films on a LaAlO3
(100) substrate, covered by a metallic oxide electrode La0.5Sr0.5CoO3
(LSCO) are demonstrated in this work. The films are fabricated by the
sol-gel method and effort was focused on thermal processing to obtain
the desired Epitaxial heterostructure. The dielectric and ferroelectri
c properties of PZT thin films were measured and it was found that the
y are as good as in the films deposited by other thin-film methods. Th
e dielectric constant and the dissipation factor of the PZT films are,
respectively, about 500 and 0.06 below 20 kHz. The remanent polarizat
ion P-r is about 27 mu C/cm(2) and the coercive field E-c is about 50
kV/cm. It was found that the ferroelectric properties were significant
ly influenced by the microstructure of the PZT layers. The present stu
dy also showed that the fatigue characteristics of the epitaxial heter
ostructure with LSCO electrodes under a reversed electrical field are
far superior to those obtained with a polycrystalline ferroelectric la
yer on Pt bottom electrodes. A low leakage current, about 3 mu A/cm(2)
at 0.5 MV/cm, was obtained for these epitaxial films. In addition, th
e optical transmittance spectrum of PZT thin films was also measured a
nd the conduction mechanism is discussed. (C) 1997 American Institute
of Physics.