FERROELECTRIC AND DIELECTRIC PROPERTIES OF NICKEL DOPED BaTiO3 THIN FILMS DEVELOPED BY SOL-GEL SPIN-COATING PROCESS

Polycrystalline thin films of BaTiO3 + xNi (BTN), here x = 0.0, 0.025, 0.05, 0.1, 0.2, 0.3 and 0.4 have been systematically obtained by sol-gel spin-coating technique. Ti-foils have been used as a substrate. Various characterization techniques have been used to study the structure, ferroelectric and dielectric properties of the BTN films such as X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe micro analyzer (EPMA) and etc. Ni-doped BaTiO3 thin films show many interesting results, such as shifting in the diffraction peaks, enhancement in ferroelectric and dielectric properties. The XRD pattern of BTN films show a slight shift in diffraction peaks to the higher 2-theeta Bragg's angle with the addition of Ni-content. Lattice constants are found using XRD plots. With the addition of Ni-dopant in BaTiO3, no phase change in the crystal structure has been observed. The SEM micrographs of BTN films display the crack free as well as uniform nature of the grown films. It is explored that the control of the process, specifically in the early stage of drying process, is essential and imperative for the synthesis of crack-free Ni-doped BaTiO3 thin films. The EPMA certifies the elemental composition of the grown samples. The electrochemical measurements of BTN films present the change in the current density (J) with the applied voltage (V). The polarization-voltage (P-V) analysis of these thin films shows the enhancement in the ferroelectric properties with Ni-content. Moreover dielectric constant vs frequency (epsilon(r) - f) measurements reveal that dielectric constant increases with Ni-dopant concentration. Among these BTN samples, the compositions BaTiO3+0.4Ni films have the highest value of the dielectric constant i.e. 2.39x10(-35) measured at 10MHz frequency at room temperature. The ferroelectric and dielectric properties of the sol-gel synthesized BTN thin films are inclined by the Ni-dopant. Doping has a vital effect on both ferroelectric as well as dielectric properties of a material that is highly appreciated in making high frequency devices.