Commercially available ZnO powder was mechanically activated in a planetary ball mill. In order to investigate the specific surface area, pore volume and microstructure of non-activated and mechanically activated ZnO powders the authors performed N 2 physisorption, SEM and TEM. Crystallite size and lattice microstrain were analyzed by X-ray diffraction method. XRD patterns indicate that peak intensities are getting lower and expend with activation time. The reduction in crystallite size and increasing of lattice microstrain with prolonged milling time were determined applying *Manuscript Click here to view linked References M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT2 the Rietveld's method. The difference between non-activated and the activated powder has been also observed by X-ray photoelectron spectroscopy (XPS). XPS is used for investigating the chemical bonding of ZnO powder by analyzing the energy of photoelectrons. The lattice vibration spectra were obtained using Raman spectroscopy.In Raman spectra some changes along with atypical resonant scattering were noticed, which were caused by mechanical activation.

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Abstract

(111)-oriented epitaxial thin films of nickel ferrite (NFO) are grown on c-plane sapphire [a-Al 2 O 3 (0001)] substrates using a chemical solution deposition technique. The processing conditions, including pyrolysis and annealing temperatures, are varied to achieve a film that shows maximum texture and epitaxy. It is shown that increasing the pyrolysis temperature to 400°C and decreasing the annealing temperature to 750°C for 10 min result in the highest degree of texture in the films. Lower film thickness also leads to a higher degree of texture. Microstructural studies confirm an in-plane epitaxial relationship between the (111) NFO film and the (0001) Al 2 O 3 substrate in two variants, [110] NFO || ½10 10 Al2O3 or ½1 100 Al2O3 .

Crystal structure and morphology of mechanically activated nanocrystalline Fe/BaTiO 3 was investigated using a combination of spectroscopic and microscopic methods. These show that mechanical activation led to the creation of new surfaces and the comminution of the initial powder particles. Prolonged milling resulted in formation of larger agglomerates of BaTiO 3 and bimodal particle size distribution, where BaTiO 3