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.

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Nanomaterials (NMs) with structural, optical, and dielectric properties are called functional or smart materials and have favorable applications in various fields of material science and nanotechnology. Pure and Co-doped MgAl2O4 were synthesized by using the sol–gel combustion method. A systematic investigation was carried out to understand the effects of the Co concentration on the crystalline phase, morphology, and optical and dielectric properties of Co-doped MgAl2O4. X-ray diffraction confirmed the cubic spinel structure with the Fd3̅m space group, and there was no impurity phase, while the surface morphology of the samples was investigated by scanning electron microscopy. The dielectric properties of the synthesized material are investigated using an LCR meter with respect to the variation in frequency (1–2 GHz), and their elemental composition has been examined through the energy-dispersive X-ray technique. The existence of the metal–oxygen Mg–Al–O bond has been confirmed by Fourier transform infrared spectroscopy. The value of the dielectric constant decreases with the increasing frequency and Co concentration. The optical behaviors of the Co2+-doped MgAl2O4 reveal that the optical properties were enhanced by increasing the cobalt concentration, which ultimately led to a narrower band gap, which make them exquisite and suitable for energy storage applications, especially for super capacitors. This work aims to focus on the effect of cobalt ions in different concentrations on structural, optical, and dielectric properties.