Anisotropic ferro- and piezoelectric properties of sol-gel-grown Bi_(3.15)Nd_(0.85)Ti_3O_(12) films with two different orientations on Pt/Ti/SiO_2/Si

摘要

Bi_(3.15)Nd_(0.85)Ti_3O_(12) thin films of two different preferred orientations were sol-gel grown on Pt/Ti/SiO_2/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 2P_r=46.4 μC/cm~2 and a piezoelectric coefficient d_(33)= 17 pm/V in a predominantly (104)/(014)-oriented film, but only 2P_r=16.7μC/cm~2 and d_(33)=5 pm/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.