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Nanowires of metal, alloy, compound, and ferrite have been electrodeposited in anodic aluminium oxide templates. The structure and magnetic properties of the nanowires are characterized by 57Fe Mössbauer spectroscopy combining with other techniques. It is found that the metal and alloy nanowires have a very strong magnetic anisotropy. The surface distribution of the magnetic moment is different from...
Arrays of γ-Fe2O3 nanowire were synthesized in anodic aluminum oxide templates. The structure, morphology and magnetic property at room temperature were characterized. Temperature-dependent Mössbauer spectra was collected and the superparamagnetic relaxation was clearly observed. Both hyperfine field and isomer shift increase with decreasing temperature. The anisotropy energy constant is determined...
Two nanogranular systems, Fe-MgF2 and Fe-SiO, were prepared by co-evaporating the each material in vacuum. Mössbauer studies of the films are described. It was shown that the Fe atoms form nanoparticles of metallic α-Fe in the Fe-MgF2 system. In contrast, the results for Fe-SiO indicate that nanoparticles of a Fe-Si alloy are formed by co-evaporating Fe and SiO.
Nanocrystalline ε-Fe3−xCoxN system having particle size in the range of 10–15 nm is synthesized by chemical route. For compositions x = 0.0–0.2, the system crystallizes in hexagonal structure and for x = 0.4–0.8, the system shows a mixture of hexagonal ε-Fe3−xCoxN and cubic α-Fe structures. The Mössbauer spectra shows the doublet...
Nanocrystalline CuFe2O4 particles are prepared by wet chemical method. The particles of various sizes are obtained by heat treatment in the temperature range 773–1073 K. The room temperature Mössbauer spectrum for all samples shows the presence of both sextet and doublet indicating the presence of superparamagnetic fractions. The isomer shift, quadrupole splitting and hyperfine field values are found...
Nanocrystalline γ-Fe2O3 was prepared by refluxing ferric nitrate in 1,4-butanediol. Characterisation was done by XRD, FTIR and Raman spectroscopy. TEM showed that the average particle size of the two samples were 9 nm and 6 nm with a small particle size distribution. FTIR and TG showed that the γ-Fe2O3 particles were capped with the diol. Mössbauer spectra of the 6 nm sample showed that the sample...
Nanostructured Fe15Mn15Cu70 alloys were prepared by high-energy ball milling. The alloying process spans grinding times from 15 minutes to 114 hours. The Mössbauer isomer shifts are analyzed at 77 K and 4.2 K as a function of the average lattice parameter determined from Rietveld analysis of the X-ray diffraction data. Evidence of two different iron sites at 77 K to account for the asymmetry of the...
By ultrasonic wave irradiation, the metallic ions in aqueous solution are reduced to metallic nanoparticles. Using the mixture solution of Au and Pd ions, core(Au)—shell(Pd) structured nanoparticles are prepared. 197Au Mössbauer spectra of core—shell structured nanoparticles contains two components, one is pure Au component due to the inner part of the Au core and the other is the positive isomer...
Phase composition of the Mg—Fe powder prepared by spark erosion is investigated using Mössbauer spectroscopy and X-ray diffraction. The results are compared with the phase analysis of MgO single crystal wafer implanted by 57Fe.
Using a co-precipitation method, a system formed by nanocrystalline Cu-Fe spinel, grain size D = 6 nm, and CuO (15 wt.%) was obtained. A Mössbauer blocking temperature (TB) of the spinel particles that lies between 100 and 200 K was observed. TB progressively increases as the sample is subjected to high-energy ball milling, being...
Nano-size particles of Ni0.5Zn0.5Fe2O4 ferrite were prepared through aerosol route. The solutions of iron, nickel and zinc nitrates were mixed in stoichiometric proportion, passed through a pneumatic nebulizer, to get very fine mist (aerosols), and a furnace at ~600°C in air atmosphere. Through various events in succession, metal atoms form ferrite in air. The average particle size was found to be...
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