Anisotropic ferro- and piezoelectric properties of sol-gel-grown Bi3.15Nd0.85Ti3O12 films with two different orientations on Pt∕Ti∕SiO2∕Si

Abstract

Bi 3.15 Nd 0.85 Ti 3 O 12 thin films of two different preferred orientations were sol-gel grown on Pt∕Ti∕SiO2∕Si. Using different heating rates during crystallization, either films containing 65% columnar grains with (104)∕(014) orientation or fine-grained films with a predominant c-axis orientation were obtained. Anisotropic ferroelectric and piezoelectric properties were determined, with a remanent polarization 2Pr=46.4μC∕cm2 and a piezoelectric coefficient d33=17pm∕V in a predominantly (104)∕(014)-oriented film, but only 2Pr=16.7μC∕cm2 and d33=5pm∕V in a predominantly c-axis-oriented film. These values confirm that the polarization vector of this material is close to the crystallographic a axis.