Ferroelectric Bi4Ti3O12–SrBi4Ti4O15 Intergrowth Thin Films Prepared by Pulsed Laser Deposition

Abstract

ABSTRACTC axis-oriented Bi4Ti3O12–SrBi4Ti4O15 (B IT-SB Ti) intergrowth epitaxial ferroelectric thin films have been grown by pulsed laser deposition (PLD) method on MgO (001) and SrTiO3 (001) substrates. The epitaxial growth of BIT-SBTi intergrowth thin films were confirmed by X-ray diffraction (XRD) θ-2θ scan, pole figure plots and reciprocal space mappings. The c axis lattice constant of the BIT-SBTi intergrowth thin film is very close to that of made up of regular stacking of one-halves of the unit cells of Bi4Ti3O12 (3.296 nm) and SrBi4Ti4O15 (4.189 nm). The annealed BIT-SBTi thin film on Pt/Ti/SiO2/Si substrate shows intergrowth structure, too, and exhibits superior ferroelectricity that the values of 2Pr and 2Ec are 32.0 μC/cm2 and 190 kV/cm, respectively. The annealed BIT-SBTi film shows that the degradation of switching charge after 1×1010 switching cycles was 16.5%. This ferroelectric enhancement is attributed to strain of pseudo-perovskite layers interacting through Bi2O2 layer. The dielectric constant and dielectric loss of the annealed BIT-SBTi film were 433 and 0.037, respectively.