Ni2+doping effect on potassium barium titanate nanoparticles: enhancement optical and dielectric properties

Abstract

Nano-structure ferromagnetic-ferroelectric composite materials produced by the sol gel method have great attention in different applications due to their desired properties and applications. Potassium Barium titanate doped with different concentrations of Ni2+ nanoparticles (K0.1Ba0.9Ti(1-x)NixO3; x = 0.0-0.3) were prepared by sol-gel process. The final nanoparticles were obtained through drying and calcination at 200 oC and 600 oC, respectively. The crystalline, nanoparticles' nature and the optical characteristics of the Ni-KBTO nanoparticles are investigated using XRD, SEM, TEM, and optical properties. The XRD and TEM results demonstrate that the Ni2+ NPs were superlatively incorporated within the semi-crystalline KBTO structure. TGA thermogram of all samples shows two weight loss events. The first event is assigned for impurities and/or adsorbed water releasing. The second event was at a higher temperature and assigned as degradation of the nanoparticles. The thermal stability was enhanced by Ni2+ incorporation. The KBTO nanoparticles exhibit enhancement optical bandgap, which decreases from 3 eV to 2.3 eV with increasing Ni2+ in KBTO NPs. This can be ascribed to the change in nanoparticles arrangement and resembles band structures between Ti4+ and Ni2+, resulting in the efficient transfer of charge carriers. The dielectric constant was in the range 106 to 107 at low frequency and about 101 to 102 at high frequency. The Curie temperature of pure Potassium barium titanate is 373 K and 328 K for Potassium barium titanate doped with 20% of Ni2+.