Modification of structural, morphological, and dielectric properties of barium calcium titanate ceramics with yttrium addition.

Barium calcium titanate (BCT) ceramics with varying yttrium doping concentrations were fabricated using the solid-state compaction process to explore the attributes of dopants. (Ba0.75Ca0.25) TiO3 and (Ba0.75Ca0.25) (YyTi(1-y)) O3 where, y = 0.00, 0.10, 0.15, and 0.20 ceramics were synthesized by pressing isostatically in pellet press apparatus, then sintered at 1250 °C with consequent cooling in furnace ambient. The structural, morphological, and dielectric properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and impedance spectroscopy interpretations, respectively. The XRD analysis revealed that the cubic BCT lattice was transformed into a tetragonal structure with Yttrium doping. Scanning electron microscopy (SEM) disclosed that yttrium doping countered the liquid phase formation of BCT as well as influenced grain development and microstructure, leading to the formation of distinct grain boundaries and improved densification. The average grain size (18-29 nm) of the Y-BCT increases as the doping level rises. At 60 Hz, it was reported that the dielectric constant obtained a maximum value of 70000 with a resistivity of 5 × 108 Ώ-cm for y = 0.15. The manifestation of the secondary phase confirmed from XRD, allocating an easy path for oxygen migration, might be responsible for the rise in oxygen vacancy, higher leakage current, and dielectric loss for y = 0.01. Co-doping of calcium and yttrium in BCT ceramics has modified the basic structure and ameliorated composites' structural stability and dielectric characteristics. The optimized sample, upon demonstrating outstanding efficiency, ought to be employed for specific uses such as energy storage devices and capacitors.

The prospect of spray pyrolyzed pure, Mn-doped, and Zn-doped nickel oxide thin films as TCO material.

Nickel Oxide films with Manganese (Mn) and Zinc (Zn) doping (NiO, Ni1-xMnxO, and Ni1-xZnxO; where x = 0, 0.02, 0.04, and 0.06) were fabricated using the spray pyrolysis technique on the glass substrates at 400 °C (673K) temperature. The XRD spectra revealed a polycrystalline nature of the films with cubic crystal structure and a favored growth orientation towards the (111) plane. The SEM micrographs revealed a smooth, homogeneous, and uniform surface, while the EDS spectra confirmed the presence of Ni, O, Zn, and Mn elements in the films. Optical analysis using UV-visible absorption spectroscopy demonstrated high transparency of the films in the visible region (400 nm-900 nm), and the transparency increased with higher Zn doping, reaching ∼85 % in Ni0.94Zn0.06O films. Conversely, Ni1-xMnxO films show a slight transmission decline with increasing Mn doping concentrations. The sheet resistance of the films was found to be decreased for low-concentration doping and again began to increase for highly doped Ni0.94Zn0.06O and Ni0.94Mn0.06O films. Among all the films, Ni0.98Zn0.02O exhibited the maximum figure of merit, showing the prospect for optoelectronic applications.