Anisotropy of ferroelectric and piezoelectric properties of Bi3.15Pr0.85Ti3O12 thin films on Pt(100)∕Ti∕SiO2∕Si substrates

This is the authors' abstract. We don't add key points for this paper.

Bi 3.15 Pr 0.85 Ti 3 O 12 (BPT) thin films with (100) (α(100)=89.1%), (117) (α(117)=83.2%), and (001) (α(001)=99.7%) orientations and a c-axis-oriented (α(001)=99.9%) Bi4Ti3O12 (BT) film were deposited on Pt(100)∕TiO2∕SiO2∕Si substrates using a metal organic decomposition process. Both the values of the remanent polarization (Pr) and coercive field (Ec) of the (001)-oriented BPT film are about 50% higher than those of the BT film with the same orientation, indicating that the ferroelectric properties of BT along the c axis can be improved by doping of praseodymium. Nevertheless, the major polarization vector of BPT is still close to the a axis rather than the c axis due to the fact that the Pr values of the (100)-oriented BPT film are about one and four times larger than those of (117)- and (001)-oriented BPT films, respectively. Based on the volume fractions of (100)-, (117)-, and (001)-oriented grains in BPT films with three orientations, the Pr values of the purely (100)-, (117)-, and (001)-oriented BPT films can be predicated to be about 28.2, 11.1, and 5.3μC∕cm2, respectively. The maximum of the piezoelectric coefficient of BPT can be demonstrated to also be close to the a axis by the piezoelectric measurements using an atomic force microscope in the piezoresponse mode.