MgTiO3 and Ba0.60Sr0.40Mg0.15Ti0.85O3 composite thin films with promising dielectric properties for tunable applications

Mg2TiO4-doped Ba0.60Sr0.40Mg0.15Ti0.85O3 (BSTM) thin films with different Mg2TiO4 concentrations were deposited on a polycrystalline alumina substrate via the sol-gel method. With the addition of Mg2TiO4, MgTiO3, MgAl2O4, and BSTM phases were formed in these composite thin films. The dielectric loss of the composite thin films decreased about one order of magnitude and the tunability still remained above 15% at a DC-applied electric field of 80 kV/cm. The dielectric constant decreased from 1040 to 388. The low dielectric constant, high tunability, and figure of merit of these composite thin films can be useful for potential tunable devices.