Enhanced tunable dielectric properties of Ba_(0.5)Sr_(0.5)TiO_3/Bi_(1.5)Zn_(1.0)Nb_(1.5)O_7 multilayer thin films by a sol-gel process

摘要

Ba_(0.5)Sr_(0.5)TiO_3(BST)/Bi_(1.5)Zn_(1.0)Nb_(1.5)O_7(BZN) multilayer thin films were prepared on Pt/Ti/SiO_2/Si substrates by a sol-gel method. The structures and morphologies of BST/BZN multilayer thin films were analyzed by X-ray diffraction (XRD) and field-emission scanning electron microscope. The XRD results showed that the perovskite BST and the cubic pyrochlore BZN phases can be observed in the multilayer thin films annealed at 700 ℃ and 750 ℃. The surface of the multilayer thin films annealed at 750 ℃ was smooth and crack-free. The BST/BZN multilayer thin films annealed at 750 ℃ exhibited a medium dielectric constant of around 147, a low loss tangent of 0.0034, and a relative tunability of 12% measured with dc bias field of 580 kV/cm at 10 kHz.