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In this research work a series of polycrystalline trivalent cation (Cr3+, La3+) substituted cobalt ferrite with general formula CoCr0.04LaxFe1.96-xO4 where 0.00 ≤ x ≤ 0.12 (in steps of 0.02) was synthesized using co-precipitation method and were sintered at 900°C for 6 hours. The phase identification and confirmation of the structure were confirmed employing the X-ray diffraction (XRD) and FTIR techniques. The size of crystallite was found on average, in the range of 53-106 nano-meters. FTIR results confirmed spinel ferrites structure. Moreover the morphological studies were observed through SEM. The elemental analysis of the samples was done by EDX while, I-V characterization of the represented sample was recorded using two probe method. The measured electrical resistivity of materials increased as dopant content increased. The magnetic behavior of the materials was studied using vibrating sample magnetometer (VSM). The saturation magnetization values and magnetic coercivity values decreased with the increase of La3+ concentration. The saturation magnetization (Ms) of the ferrite materials decreased with the reduction of size.

In this work, We have successfully grown the crystalline Tin Oxide (SnO 2 ) micro-sheets by hydrothermal technique without using any catalyst. We also able to controlled the thickness of grown sheets by modulating the growth temperature and have reported the thickest micro-sheets (5 µm thick) for the first time. X-ray diffraction (XRD) studies confirm the tetragonal crystalline structure of grown SnO 2 and particle size was found to be increased from 2 to 15 nm as the synthesis temperature increased from 50 to 250 °C. SEM images have shown the micro-sheets like morphology of synthesized samples and the thickness of sheets increased from 1.4 to 5.1 ± 0.01 µm as the growth temperature increased from 150 to 250 °C respectively. Raman spectroscopy measurements showed a dominant peak at 639 cm −1 which is related to A 1g mode of SnO 2 . The intensity of A 1g mode increased with growth temperature supporting the XRD results that the crystal structure of grown SnO 2 sheets improved with increasing growth temperature. Furthermore, the degree of crystanality, calculated from Raman data, increased to 68% at growth temperature 250 °C. The analysis of UV–Visible data demonstrated that increasing temperature from 150 ℃ to 250 ℃ causes the shift in the optical absorption edge from 280 to 290 nm respectively.

In this paper, we have reported the growth of Zn2GeO4 thin film and investigated its potential for thermoelectric power generation applications. Zn2GeO4 alloy thin film was grown on Indium coated glass substrate by the evaporation of Zn and Ge metals with constant oxygen gas flow rate of 100 sccm in tube furnace. The grown film was cut into pieces and annealed at various temperatures from 500° to 700°C with a step of 100 °C in a programmable furnace for one hour. The structure of as grown and annealed thin films was verified by XRD and Raman spectroscopy measurements. The XRD data evident that Zn2GeO4 alloy hexagonal structure along with GeO2 and ZnO phases were observed at annealing temperatures 600 and 700 °C but below this temperature no alloy phase was detected by XRD and Raman Spectroscopy. To calculate the thermoelectric properties, temperature dependent Seebeck measurements were performed in the temperature range of 25–100 °C. It was observed that the value of Seebeck coefficient was increased from 91 to 847 μV/K as the annealing temperature increases from 500° to 700°C. This behavior was explained as; high temperature causes stress and cracks in the grown films which may induce electric and thermal discontinues at tips of cracks which cause high thermoelectric concentration. Scanning electron microscope images verified the development of cracks in the samples as annealing temperature increases. The behavior of Seebeck coefficient with the measurement temperature was also observed and explained in detail. The high value of Seebeck coefficient suggested that this material can be a potential candidate for thermoelectric power generation applications in near future.