Structure and dielectric properties of cubic Bi<inf>2</inf>(Zn <inf>1/3</inf>Ta<inf>2/3</inf>)<inf>2</inf> O<inf>7</inf> thin films

Abstract

Pyrochlore Bi2(Zn1/3Ta2/3)2 O7 (BZT) films were prepared by pulsed laser deposition on Pt/TiO2/SiO2/Si substrates. In contrast to bulk monoclinic BZT ceramics, the BZT films have a cubic structure mediated by an interfacial layer. The dielectric properties of the cubic BZT films [ε∼177, temperature coefficient of capacitance (TCC) ∼-170 ppm/°C] are much different from those of monoclinic BZT ceramics (ε∼61, TCC ∼+60 ppm/°C). Increasing the thickness of the BZT films returns the crystal structure to the monoclinic phase, which allows the dielectric properties of the BZT films to be tuned without changing their chemical composition. © 2009 American Institute of Physics