Alumina (Al 2 O 3) has been synthesized through combustion synthesis (CS) technique. The calcined products were characterized using X-ray diffractional analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermo-gravimetric analysis (TGA). TG-DTA results reveal the various stages involved in transition from γ-phase to α-Al 2 O 3 phase. The first phase γ-Al 2 O 3 was presented in the temperature range from 600˚C-875˚C as deduced from the XRD patterns with cubic crystal structure. The second stage occurs in the temperature range from 900˚C-1000˚C. In the final step, above 1000˚C, the aluminium oxide appears completely as α-Al 2 O 3 , showing high crystallinity. The particle sizes are closely related to γ-to α-Al 2 O 3 phase transition.

The present chapter summarizes the synthesis and characterization of Zinc Copper (ZnCu) ferrites due to their wide range of applications in many areas. ZnCu ferrites are soft magnetic materials that have exceptional electrical, magnetic, and optical properties. ZnCu ferrites possess high resistivity, permeability, permittivity, saturation magnetization and low power losses, and coercivity. The above features of ZnCu ferrites find application in designing transformers, transducers, and inductors. Ferrites are also used in magnetic fluids, sensors, and biosensors. Apart from these advantages, they play a vital role in practical appliances like mobile, laptops, mobile chargers, refrigerators, washing machines, microwave ovens, printers, and so on. Therefore, the present focus is on the literature of techniques of the synthesis, their characterization, the effect of doping on the behavior of ZnCu ferrite, and, finally, their potential application in technology.

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Pure and Cadmium (Cd) doped Cerium oxide nanoparticles (CeNPs) have been synthesised by the simple chemical co-precipitation technique. Cadmium ions of concentrations 1, 3 and 5 mol% were doped to investigate their influence on the structural and optical properties of CeO 2. The synthesised samples have been subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and high-resolution transmission electron microscopy (HRTEM). The XRD and Raman patterns have witnessed the cubic structure of the cerium oxide nanoparticles. The average particle size of CeO 2 was found to be around 10 nm. SEM image has also ascertained that the grain size of pure CeO 2 appeared is bigger than that of the Cd-doped, which intern indicates the grain growth upon doping. Besides, the antibacterial activity of the cadmium doped cerium oxide nanoparticles against some human pathogens revealed that they have exhibited the maximum zone of inhibition against gram-positive bacteria than the gram-negative species. Further, the cytotoxic effect of Cd-doped CeO 2 sample is examined in cultured (MCF-7, A549 and Hep-2) cell.