Giant dielectric phenomenon of Ba0.5Sr0.5TiO3/CaCu3Ti4O12 multilayers due to interfacial polarization for capacitor applications

Abstract Ba 0.5 Sr 0.5 TiO 3 /CaCu 3 Ti 4 O 12 (BST/CCTO) multilayers with different stack sequences were deposited on LaNiO 3 (LNO)/SiO 2 /Si substrates by a sol-gel process. The dielectric properties of BST/CCTO multilayers are significantly affected by the deposition sequence, the layer thickness and the impurities, effects that are interpreted using the Maxwell-Wagner interfacial polarization model. Impurities are generated by elemental interdiffusion at the interfaces of BST/CCTO, and less at the interfaces of BST/LNO and CCTO/LNO. The dielectric permittivity of the CCTO/BST/LNO/SiO 2 /Si sample reaches 352,200 at 10 kHz, and stabilizes above 20,000 in the range of 100 kHz to 1 MHz. This work demonstrates an effective approach to enhance dielectric properties for film capacitor applications by constructing multilayers with specific deposition sequences and layer thicknesses.