Effect of orientation on the dielectric and piezoelectric properties of 0.2Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}--0.8Pb(Zr{sub 0.5}Ti{sub 0.5})O{sub 3} thin films

0.2Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}--0.8Pb(Zr{sub 0.5}Ti{sub 0.5})O{sub 3} (0.2PMN--0.8PZT) thin films were deposited on Pt(111)/Ti/SiO{sub 2}/Si [Pt(111)] and Pt(200)/SiO{sub 2}/Si [Pt(200)] substrates by a sol--gel method, and the effect of orientation on the piezoelectric and dielectric properties of 0.2PMN--0.8PZT thin films was investigated. The 0.2PMN--0.8PZT thin films on Pt(111) and Pt(200) showed strong (111) and (100) preferred orientations, respectively. The spontaneous polarization of the (111) oriented film was higher than that of the (100) oriented film. However, the (100) oriented film showed a higher dielectric constant (K) and transverse piezoelectric coefficients (d{sub 31}) than the (111) oriented film. Because the spontaneous polarization direction of the (100) oriented film is more tilted away from the normal to the film surface than that of the (111) oriented film, the dielectric constant and the transverse piezoelectric coefficient (d{sub 31}) of the (100) oriented film were enhanced. {copyright} 2001 American Institute of Physics.