Perovskite ferroelectric and multiferroic RF tunable capacitors
ABO3 type Perovskite ferroelectric materials shows great potential for RF/microwave passive tuning. Especially Ba1-xSrxTiO3 (0 = x = 1) (BST) shows a high dielectric constant, a low loss tangent, and a high tuning as a function of electric field. Because of oxygen vacancy traps in the lattice, it shows high leakage current and RF loss. In the presentation, synthesis and characterization of sol-gel based Ag-doped BST is presented. Metal-insulator-metal (MIM) RF capacitors shows an improved RF performance with reduced leakage current and loss tangent. The second part of the talk discusses a new type of multiferroic material Fe1-xSrxTiO3 (0 = x = 1) (FST) and its RF/microwave characteristics. FST shows both ferroelectricity and ferromagnetism. Its dielectric constant and electric field dependent tunability is inferior to those of BST while it shows a tunable magnetodielectric effect, i.e. a magnetic field dependent dielectric constant change.