Evolution Of Nanocrystalline Phases Research Articles

Regularities of formation of nanocrystalline particles in titanium subgroup dioxides

Trends in formation and evolution of nanocrystalline phases in TiO2, ZrO2, and HfO2 powders were studied. The stability of metastable phases increases in the order of HfO2 > ZrO2 > TiO2, and the probability of formation of thermodynamically stable phases increases in the order of TiO2 > ZrO2 > HfO2. The enthalpies of formation were determined for TiO2, ZrO2, and HfO2 nanocrystallites, as well as the activation energies of their subsequent growth. For TiO2 and ZrO2, a phenomenological model was advanced to describe nanocrystallite formation and subsequent polymorphic transformations.

Evolution of nano-crystalline phases with post-annealing of nitrogen irradiated Fe/Co bilayers

Effect of deposition order on the magnetic behavior of magnetic bilayers has been investigated. Different out-of-plane texture has been obtained on reversing the deposition order of Co/Fe bilayer, prepared by ion beam sputtering method. Si(substrate)/Fe/Co shows higher coercivity value compared to Si(substrate)/Co/Fe. Annealing of as-deposited specimens does not show any change in the coercivity value. Nitrogen-ion implantation with a fluence of 5×1016ions/cm2, drastically increases the coercivity value of Substrate/Fe/Co film. In situ annealing of Substrate/Fe/Co, does not show any structural changes in the film, while Substrate/Co/Fe shows the phase transformation from hcp Co to fcc Co, and the appearance of new peaks in the EDXRD pattern suggest the formation of new nano-crystalline phase.