Composition dependence of ferroelectric and piezoelectric properties of epitaxial (1 - x)Ba(Zr <inf>0.2</inf> Ti <inf>0.8</inf> )O <inf>3</inf> -x(Ba <inf>0.7</inf> Ca <inf>0.3</inf> )TiO <inf>3</inf> thin films prepared by pulsed laser deposition

Abstract Lead-free (1 - x)Ba(Zr 0.2 Ti 0.8 )O 3 -x(Ba 0.7 Ca 0.3 )TiO 3 (BZT-xBCT) (x = 0.3, 0.4, 0.5, 0.6, 0.7) thin films were deposited on SrRuO 3 (SRO)-electroded (0 0 1)-oriented SrTiO 3 (STO) single crystal substrates by pulsed laser deposition (PLD). X-ray diffraction and selected area electron diffraction (SAED) patterns verified epitaxial growth for all the thin films. High ferroelectric activities were evidenced by the well-defined polarization-electric field hysteresis loops. Both structural and physical properties of the thin films demonstrated a strong composition dependence and an MPB-like behaviour was found at around x = 0.5, which is in agreement with that of its bulk counterparts. The superior ferroelectric and piezoelectric responses were attained at x = 0.5 with remanent polarization P r of 17.8 μC/cm 2 and piezoelectric coefficient d 33 of 100 ± 5 pm/V