Enhanced dielectric properties of nanocrystalline (Ba0.65Sr0.35)TiO3 thin films grown on CaRuO3 buffer layers.

Highly (100)-oriented and (110)-oriented (Ba0.65Sr0.35)TiO3 (BSTO) and (Ba0.65Sr0.35)TiO3/CaRuO3 (BSTO/CRO) heterostructure thin films, have been grown on Pt/Ti/SiO2/Si substrates prepared by pulsed laser deposition (PLD). The structure and surface morphology of the films have been characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The dielectric constants of the films changes significantly with applied dc bias field and have high tunability of 76.3% and 78.1% at an applied field of 256.3 kV/cm, respectively for BSTO and BSTO/CRO thin films on Pt/Ti/SiO2/Si substrates. The tunability of the BSTO/CRO heterostructure thin films on Pt/Ti/SiO2/Si substrate was higher than that of the BSTO thin films on Pt/Ti/SiO2/Si substrate. The high tunability has been attributed to the (110) texture of the films and lager grain sizes.