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In this work, we investigated the impact of Mn substitution on the morphological, structural, and optical properties of barium strontium titanate (BST) with the formula Ba0.92Sr0.08Ti1−xMnxO3 (x = 0.00, 0.10, 0.20) fabricated using the solid-state reaction technique. The morphological and structural properties were studied using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The optical properties of the samples were analyzed using photoluminescence (PL), Fourier transform infrared (FTIR), and Raman spectroscopy. SEM micrographs displayed nearly spherical grains. The phase formation, lattice structure, crystallite size (D), strain (ε), and dislocation density (δ) of the Mn-doped BST ceramics were examined from the recorded XRD patterns using the Scherrer and Williamson–Hall (W–H) models, which showed that the crystallite size increased and the lattice strain and dislocation density decreased with increasing doping concentrations. FTIR results for the pristine sample of BST revealed that the absorption peak at a wavenumber of 470 cm−1 was shifted to 1250 cm−1 for Mn-doped BST concentrations. The Raman results indicated that the number of modes decreased with the increase in the Mn2+ concentrations. PL spectra showed an emission band centered at 60–659 nm, indicating redshift behavior. The analysis using XRD, SEM, FTIR, and Raman spectroscopy revealed that the concentration x = 0.20 is appropriate for use in microwave devices and other electro-optical applications. [ABSTRACT FROM AUTHOR]

Tungsten doped Barium Titanate (BT) with composition BaW0.05Ti0.95O3 (BWT) were prepared by using ball milling technique for different hours (10 h, 20 h and 30 h). In the present paper, the microstructural, dielectric and impedance studies are discussed. The microstructural studies using XRD data reveals the formation of single phased tetragonal structure and perovskite structure. The dielectric properties of BT nanoceramics were significantly enhanced by the partial replacement of W (at B site) showing the diffuse phase transition at 80°C. Dielectric loss rises as the temperature rises. There is increase in charge carrier mobility which results in increased polarization and significant dielectric loss. Additionally, compared to the un-milled BWT ceramic sample, the 30 h milled had superior dielectric characteristics with high dielectric constant and reduced loss. The nature of the phase transition was confirmed by the Curie-Weiss law and the ferroelectric analysis was carried by well-established P-E loops. The impedance studies were carried out by plotting Nyquist plots. The ac conductivity plot follows Arrhenius relation and the calculated activation energy confirms the negative temperature coefficient of resistance (NTCR) behavior of the material. [ABSTRACT FROM AUTHOR]