The lead-free Ca­(Sn x Ti1–x )­O3, (0 ≤ x ≤ 0.8) sample has been successfully prepared through the ball milling process, sintered at 1200 °C for 3 h. The structural, morphological, vibrational, and microwave dielectric properties of synthesized samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and impedance analysis. All the samples have an orthorhombic phase structure with a space group of Pbnm formation, and the crystalline size and strain changes with respect to Sn4+ doping were observed in the XRD analysis. From a morphological point of view, on increasing the content “x”, the grain size reduces from 3.29 to 1.37 μm. The existence of vibrations and the bridging stretching mode of Ti–O–Ti and Ti–O–Sn both are associated with the broadband in the region below 800 cm–1 verified by FT-IR. The variation in electrons hopping off the host compound with respect to Sn4+ ions was analyzed in AC conductivity. The changes of dielectric properties such as complex permittivity, modulus spectroscopy, and dielectric loss at room temperature with a different frequency range of 1.00–2.00 GHz are discussed.

The structural, microstructural, and microwave dielectric properties of Ba1–x Sr x Ti4O9, (0.0 ≤ x ≤ 0.06) ceramics samples synthesized by a conventional route were investigated. These structural, microstructural, and dielectric properties were recorded using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) and impedance analyzer spectroscopies. Ti–O octahedral distortion was observed due to Sr2+ addition. The microwave dielectric properties were interrelated with various Sr2+ concentrations. Excellent microwave dielectric properties, i.e., high relative permittivity (ϵr = 71.50) and low dielectric loss (tan δ = 0.0006), were obtained.

We investigate the impact of Ni insertion on the structural, optical, and magnetic properties of Ba0.8La0.2Fe12–x Ni x O19 hexaferrites (Ni substituted La-BaM hexaferrites). Samples were prepared using the conventional co-precipitation method and sintered at 1000 °C for 4 hours to assist the crystallization process. An analysis of the structure of the samples was carried out using an x-ray diffraction (XRD) spectrometer. The M-type hexagonal structure of all the samples was confirmed using XRD spectra. The lattice parameters a and c were found to be in the ranges of 5.8925±0.001 nm–5.8952±0.001 nm and 23.2123±0.001 nm–23.2219±0.001 nm, respectively. The M-type hexagonal nature of the prepared samples was also indicated by the presence of corresponding FT-IR bands and Raman modes in the FT-IR and Raman spectra, respectively. EDX results confirmed the successful synthesis of the samples according to the required stoichiometric ratio. A UV-vis spectrometer was used to record the absorption spectra of the prepared samples in the wavelength range of 200 nm–1100 nm. The optical energy bandgap of the samples was found to be in the range of 1.21 eV–3.39 eV. The M–H loops of the samples were measured at room temperature at an applied magnetic field range of 0 kOe–60 kOe. A high saturation magnetization of 99.92 emu/g was recorded in the sample with x = 0 at a microwave operating frequency of 22.2 GHz. This high value of saturation magnetization is due to the substitution of La3+ ions at the spin-up (12k, 2a, and 2b) sites. The Ni substitution is proven to be a potential candidate for the tuning of the optical and magnetic parameters of M-type hexaferrites. Therefore, we suggest that the prepared samples are suitable for use in magneto-optic applications.

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In the present work, pure and Cr-doped MoO3 microrods were successfully prepared through the sol gel auto combustion method. The phase evaluation and microstructural, dielectric, and optical properties of synthesized samples were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and an impedance analyzer (1 MHz–3 GHz). All the samples showed hexagonal structure with space group (P63). According to Vegard’s law, lattice parameters increase with the increase in chromium (Cr3+) contents. In addition, the Williamson–Hall (W–H) plot was drawn for evaluating the micro-strain (εW-H) and crystallite size (DW-H) parameters. From microstructural analysis it was found that the size of microrods increased along with Cr3+ contents. Decreasing band gap energy was observed (from 2.98 to 2.71 eV) with increasing Cr3+ contents. The variation of the dielectric constant and tangent loss of MoO3 microrods with respect to frequency were analyzed.