Influence of preheating on crystallization and growing behavior of Ce and Mn doped Ba0.6Sr0.4TiO3 film by sol-gel method

Cerium and manganese codoped Ba0.6Sr0.4TiO3 (CeMn-BST) film and pure BST, Ce-BST and Mn-BST films were prepared. Influence of preheating on film crystallization and growing behavior was studied. X-ray diffraction (XRD) reveals that all films mainly grow along (110) orientation and show cubic ABO(3) perovskite structures, and the preheating promotes Ce3+ and Mn4+ ions enter into B-sites and substitute Ti4+ ions. Preheating enhances crystallization and causes the strongest crystallization with CeMn-codoping. Atomic force microscopy (AFM) exhibits that films preheated show layered growth, while those not preheated show island growth, which are related to layer number and doping. Therefore, the films preheated show larger permittivities, higher tunabilities, and lower dielectric losses except the pure BST film and higher figures of merit (FOMs). Preheating with CeMn-codoping causes best dielectric properties with 56% tunability, 0.0037-0.0091 loss and near 150 FOM, meeting the needs of tunable microwave applications. (c) 2012 Elsevier B.V. All rights reserved.