Composition-dependent structures and properties of Bi4Ti3−xZrxO12 thin films

Thin films of B-site substituted Bi4Ti3O12 (BTO) by Zr, Bi4Ti3−xZrxO12 (BTZx, x=0.2, 0.5, 1.0 and 1.5), were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Structures and properties of the films were studied as functions of Zr composition. Structure characterization was conducted by X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. The Zr substitution does not change the layered structures of the BTZx. However, with increasing x from 0.2 to 1.5, the vibration modes of the TiO6 octahedra weaken greatly, which is responsible for the corresponding weakening ferroelectricity the remnant polarizations are 14.8, 11.2, 2.4, and 1.4 μC/cm2, respectively. Additionally, the Zr substitution cannot improve the fatigue-resistance of BTZx significantly. After 7.22×109 switching cycles, the nonvolatile polarization decreases by 30.3 and 64.9% of the initial values for x=0.2, and 0.5, respectively. The dielectric properties of these films are also investigated briefly. The relationship between the structures and properties is established experimentally.