Effect of oxygen pressure on structure and properties of Bi1.5Zn1.0Nb1.5O7 pyrochlore thin films prepared by pulsed laser deposition

The Bi2O3-ZnO-Nb2O5 (BZN) cubic pyrochlore thin films were prepared on Pt/TiO2/SiO2/Si(1 0 0) substrates by using pulsed laser deposition process. The oxygen pressure was varied in the range of 5-50 Pa to investigate its effect on the structure and dielectric properties of BZN thin films. It is found that oxygen pressure during deposition plays an important role on structure and other properties of BZN films. The BZN films deposited at temperature of 650 °C and at O2 pressure of 5 Pa have an amorphous BZN and Nb2O5 phases but exhibits a cubic pyrochlore structure with a preferential (2 2 2) orientation when the oxygen pressure increases to 10 Pa. Dielectric constant and loss tangent of the films deposited at 10 Pa are 185 and 0.0008 at 10 kHz, respectively. The dielectric tunability is about 10% at a dc bias field of 0.9 MV/cm.