Dielectric enhancement and, Maxwell-Wagner effects in polycrystalline ferroelectric multilayered thin films

Dielectric enhancement was observed in polycrystalline BaTiO3/Ba0.6Sr0,4TiO 3 multilayered thin films deposited layer-by-layer on Pt/Ti/SiO2/Si substra tes via pulsed laser deposition. The dielectric constant of the films was e nhanced more than four times with the decrease of the individual layer thic kness down to 30 nm, while the dielectric loss was kept at a low level comp arable to that of the solid solution Ba0.8Sr0.2TiO3 thin films. The Maxwell -Wagner model is proposed to explain the experimental data, which can predi ct both the dielectric enhancement and frequency dependence when the indivi dual layer thickness is more than 40 nm.