Thickness and temperature dependences of dielectric properties of {111}-oriented epitaxial Pb(Mg1/3Nb2/3)O3 and 0.6Pb(Mg1/3Nb2/3)O3–0.4PbTiO3 films

Abstract

The effects of film thickness and composition on crystal structure and dielectric properties were investigated for {111}-oriented epitaxial Pb(Mg1/3Nb2/3)O3 (PMN) and 0.6Pb(Mg1/3Nb2/3)O3–0.4PbTiO3 (0.6PMN–0.4PT) films of various thicknesses grown on (111)cSrRuO3//(111)SrTiO3 substrates by pulsed metal organic chemical vapor deposition (MOCVD). When the film thickness of {111}-oriented PMN films increased from 500 to 1300 nm, the relative dielectric constant at room temperature increased from 1600 to 2800 at 10 kHz. This tendency was similar to our previous result for {100}-oriented PMN films. On the other hand, the relative dielectric constant at room temperature slightly increased from 2500 to 2700 at 10 kHz with the increase in film thickness from 750 to 2500 nm in the case of {111}-oriented 0.6PMN–0.4PT films. PMN films show strong frequency dependences of maximum relative dielectric constant against temperature, εr(max), and the temperature of εr(max), T(max), together with a strong thickness dependence. On the other hand, 0.6PMN–0.4PT films show small frequency dependences of εr(max) and T(max) together with a small film thickness dependence. These results show a strong film composition dependence of the dielectric properties of the films in a PMN–PT system such as frequency and thickness.