Ba0.5Sr0.5TiO3-Bi1.5Zn1.0Nb1.5O7 composite thin films with promising microwave dielectric properties for microwave device applications

摘要

Crack-free, dense, and uniform Ba0.5Sr0.5TiO3(BST)-Bi1.5Zn1.0Nb1.5O7(BZN) composite thin films were deposited on (100) LaAlO3, (100) SrTiO3, and (100) MgO substrates via a pulsed laser deposition, using a combined target of BST and BZN ceramics. Phase composition and microstructure of the BST-BZN thin films were characterized by x-ray diffraction and scanning electron microscopy. The films, on LAO, STO, and MgO substrates, showed zero-field microwave (similar to7.7 GHz) dielectric constants of 471, 435, and 401, dielectric loss tangents of 0.0048, 0.0043, and 0.0037, and dielectric tunabilities of 6.2%, 6.0%, and 5.7% at similar to8.1 kV/cm, respectively. The good physical and electrical properties of the BST-BZN composite thin films make them promising candidates for microwave device applications. (C) 2004 American Institute of Physics.