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Single-phase cobalt ferrite (CoFe2O4) nanopowder, with average particle size ∼20 nm, has been synthesised using an ethylene diamine tetra acetic acid precursor-based method. CoFe2O4nanopowder was obtained by calcining precursor at 550°C for 4 h in air. The change of microstructure of the synthesised CoFe2O4with increasing sintering temperature was studied using scanning electron microscopy. DC electrical resistivities of unsintered and sintered samples were measured using a two-probe method. Room temperature magnetic hysteresis measurement revealed that the synthesised CoFe2O4nanopowder exhibited ferromagnetic behaviour at room temperature with saturation magnetisation of 67.55 emu/g and coercivity of 1645.24 Oe. [ABSTRACT FROM PUBLISHER]

Abstract: Biosynthesis of gold nanoparticles has been achieved via reduction of an aqueous chloroauric acid solution with dried biomass of a freshwater epilithic green alga, Prasiola crispa, collected from a high altitude river ecosystem in Arunachal Pradesh state, India. The synthesized nanoparticles were characterized by UV–visible, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), FT-IR, and DLS studies. The UV–visible spectrum of the synthesized gold nanoparticles showed a surface plasmon resonance (SPR) around 535nm after 12h. The powder XRD pattern furnished evidence for the formation of face-centered cubic structure of gold having average crystallite size 9.8nm. The TEM images showed the nanoparticles to be nearly spherical in shape with sizes in the range of 5–25nm. [Copyright &y& Elsevier]