Structure and piezoelectric properties of sol–gel-derived 0.5 Pb[Yb1/2Nb1/2]O3–0.5 PbTiO3 thin films

0.5 Pb[Yb1/2Nb1/2]O3–0.5 PbTiO3 thin films were deposited on (111) Pt/Ti/SiO2/Si substrates by sol–gel processing using a thin Pb(Zr0.52Ti0.48)O3 seed layer. X-ray diffraction analysis and scanning electron microscopy revealed that the films were strongly (111) oriented, mimicking the orientation of the (111) Pt/Ti/SiO2/Si substrate. No pyrochlore phase was observed by x-ray diffraction and the films had a uniform grain size of about 50–60 nm. The dielectric permittivity and loss factor varied only slightly with frequency in the range of 100–10 000 Hz. At 1 kHz, the dielectric permittivity was 1025 and dielectric loss was 0.028. The films exhibited good ferroelectric and piezoelectric properties. The remanent polarization (Pr) was 30 μC/cm2. The effective transverse piezoelectric e31,f coefficient (−4.8 C/m2) of the films was measured using a modified wafer flexure method.