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Nanocrystals of magnetite (Fe 3 O 4 ) were prepared by sol-gel technique. The prepared nanocrystals were characterized for phase by powder X-ray diffraction (XRD) of the samples annealed at successively higher temperature. The magnetite phase was formed during the annealing of the synthesized powder at 400 °C for a few hours. The Fourier transform infrared spectroscopy (FTIR) was performed to analyze the functional groups in the material. The energy dispersive X-ray diffraction (EDAX) was performed for chemical composition analysis. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques were used to analyze the morphology of nanocrystals and for estimating their average size. The results confirm the formation of Fe 3 O 4 nanocrystals of the sizes ~20-50 nm.

Fe doped lithium niobate, LiNbO3 (LN), crystals were grown successfully by the Czochralski technique. Growth parameters were optimized to get a constant diameter crystal without using the automatic diameter control (ADC) system. A broad absorption band centered at 488 nm has been observed in the absorption studies due to 2eg and 2t2g transition. The significant red shift in UV absorption edges indicates a decrease in the Li/Nb ratio in the Fe doped LiNbO3 crystals. Energy dispersive analysis by X-ray (EDAX) shows that the crystal is doped successfully with the desired Fe concentration. Birefringence interferometry was used for quantitative assessment of the optical quality of the grown crystal.