Composition Dependence of Ferroelectric and Piezoelectric
Properties in Lead-Free Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 Epitaxial
Thin Films Prepared by Pulsed Laser Deposition
1School
Q.R. Lin1, R. Ding1, B.C. Luo1, D.Y. Wang1,a
of Material Science and Engineering, The University of New South Wales,
Kensington, NSW 2052, Australia
e: dy.wang@unsw.edu.au
(1-x) BaZr0.2Ti0.8O3-xBa0.7Ca0.3TiO3 (BZT-xBCT) has been identified as a
promising lead-free piezoelectric material due to its high piezoelectric coefficients in
bulk form at room temperature morphotropic phase boundary (MPB) composition
(x=0.5). However, studies on physical properties of BZT-xBCT thin films are still
insufficient. In this work, BZT-xBCT thin films with x = 0.3 - 0.7 were deposited on
SrRuO3 electroded SrTiO3 (001) single crystal substrates by pulsed laser deposition.
X-ray diffraction and high resolution transmission electron microscope confirmed a
highly epitaxial growth of all the films. Both structural and electrical properties
demonstrated strong dependence on composition. The optimal ferroelectric and
piezoelectric responses were attained in the BZT-0.5BCT thin films with a remanent
polarization Pr = 17.8 μC/cm2 and a piezoelectric coefficient d33=100±5 pm/V,
indicating an MPB-like behaviour. It should be noted that the observed piezoelectric
coefficient of our BZT-0.5BCT thin film is comparable to that of PZT thin films,
suggesting the BZT-xBCT thin films are promising lead-free alternative for high
performance microelectronic and energy harvesting applications.