Enhanced dielectric properties of multilayered BiFeO3/BaTiO3 capacitors deposited by pulsed laser deposition

Abstract

We report on dielectric studies of BiFeO3(BFO)/BaTiO3(BTO) multilayer structure fabricated by pulsed laser deposition technique. Multilayered capacitors were prepared by increasing number of alternating individual layers from 2 to 7 while maintaining the total thickness of the layered structure as 350 nm. The dielectric constant of the BFO/BTO multilayer structure was significantly increased to 772 (at 1 kHz) and the dielectric loss decreased to 1.08 (at 1 kHz) in comparison to that of bare BFO and BTO thin films of 350 nm thickness. Further the dielectric constant increased with increasing number of individual layers. The increase in dielectric constant is related to the enhancement of ferroelectricity and reduced leakage current which is due to the induced stress at the interface of BFO and BTO layer in the multilayer capacitor. A high value of ferroelectric polarization (∼ 99.80 µC/cm2) was obtained for 6-layer BFO/BTO structure. The multilayer structure exhibited superior dielectric properties and can be undeniably used as the dielectric layer in silicon-based capacitors and tunable microwave device applications.