Ferroelectric and piezoelectric properties of bismuth layered thin films grown on (1 0 0) Pt electrodes

The effect of film orientation on piezoelectric and ferroelectric properties of bismuth layered compounds deposited on platinum coated silicon substrates was investigated. Piezo-force microscopy was used to probe the local piezoelectric properties of Bi4Ti3O12, CaBi4Ti4O15 and SrBi4Ti4O15 films. Our measurements on individual grains clearly reveal that the local piezoelectric properties are determined by the polarization state of the grain. A piezoelectric coefficient of 65 pm/V was attained after poling in a grain with a polar axis very close to the normal direction. The piezoelectric coefficient and the remanent polarization were larger for a–b axes oriented than for c-axis-oriented films.