Dielectric and transverse piezoelectric properties of sol-gel-derived (001) Pb[Yb1/2Nb1/2]O3–PbTiO3 epitaxial thin films

(1−x) Pb [ Yb 1/2 Nb 1/2 ] O 3 –x PbTiO 3 (PYbN–PT, x=0.5) epitaxial thin films were deposited on (001) SrRuO3/(001) MgO substrates by sol-gel processing. X-ray diffraction analysis revealed that the films were pyrochlore-free (001) epitaxial films when crystallized at 750 °C for 1 min. The dielectric permittivity and loss factor varied only slightly with frequency in the range of 100 to 10 000 Hz. At 1 kHz, the dielectric permittivity was 870 and the dielectric loss was 0.03 at room temperature. Compared with (111) PYbN–PT films, (001) PYbN–PT films exhibited better ferroelectric and piezoelectric properties. The remanent polarization (Pr) was 37 μC/cm2. The effective transverse piezoelectric e31,f coefficient of the films were −10.2 C/m2 when films were poled at room temperature. Enhanced piezoelectric properties were obtained using unique two-step method poling the PYbN–PT films at higher temperatures.