02286nas a2200217   4500008004100000020001800041245009800059210006900157260009600226300001200322520144500334100002001779700001801799700001401817700001901831700002201850700002501872700002301897700001901920856012901939       2005                        eng d  a1-57498-218-400aMagnetic properties of nanosized ferrite powders synthesized by microwave-hydrothermal method0 aMagnetic properties of nanosized ferrite powders synthesized by   aSan Francisco, CAbAmer Ceramic Soc, 735 Ceramic Place, Westerville, OH 43081-8720 USAcAUG  a143-1483 a<p>Nanosized powders of Fe3O4 and MgFe2O4 are synthesized by microwave-hydrothermal (MH) method. The ferrite powders thus obtained are characterized by powder X-ray diffraction, Mossbauer spectroscopy, scanning and transmission electron microscopies, vibrating sample magnetometer and AC magnetic susceptibility studies. Stoichiometric, nanosized (similar to 34 nm) Fe3O4 particles, having cubic symmetry with a(0) approximate to 8.39 angstrom, are obtained when molar ratio of Fe/NaOH used for the synthesis is 0.133. On the other hand, non-stoichiometric Fe3O4 is obtained when Fe/NaOH molar ratio is increased to 0.4. Though the powder XRD patterns of both stoichiometric and non-stoichiometric Fe3O4 are identical, Mossbauer spectroscopic studies showed different features in terms of asymmetry, intensity, isomer shift, etc. Saturation magnetization, M-s = 70 emu/g and coercivity, H-c = 178 Oe, at room temperature, are obtained for stoichiometric Fe3O4 powders. In the case of MgFe2O4, spherical, nanosized (similar to 3 nm) powders with cubic symmetry (a(0) approximate to 8.30 angstrom) and having very narrow size distribution are obtained under the MH conditions. The temperature and field dependent magnetic measurements on MgFe2O4 powders confirmed the existence of superparamagnetic state in this material with a superparamagnetic blocking temperature of 38 K below which typical magnetic hysteresis behaviour is observed.</p>1 aKhollam, Y., B.1 aDhage, S., R.1 aVerma, S.1 aPotdar, H., S.1 aDeshpande, S., B.1 aJoy, Pattayil, Alias1 aDate, Sadgopal, K.1 aSoohoo, R., F.  uhttps://library.ncl.res.in/content/magnetic-properties-nanosized-ferrite-powders-synthesized-microwave-hydrothermal-method-002032nas a2200313   4500008004100000022001400041245010400055210006900159260007900228300001400307490000700321520096200328653001601290653002701306653001901333653002101352100002001373700002501393700002101418700001401439700002201453700002201475700001701497700001601514700002201530700002301552700001401575856012901589       2008                        eng d  a1044-580300aMossbauer spectroscopic investigations of nanophase iron oxides synthesized by thermal plasma route0 aMossbauer spectroscopic investigations of nanophase iron oxides   a360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USAbELSEVIER SCIENCE INCcSEP  a1215-12200 v593 a<p>Magnetic nanoparticles of iron oxide were synthesized by transferred arc plasma induced gas phase condensation method. Structural, morphological and magnetic studies of the as synthesized powder were carried out using X-ray diffraction, transmission electron microscopy and Mossbauer spectroscopy. These studies have revealed the simultaneous nucleation and condensation of different magnetic phases with a broad size distribution of the nanoparticles which is peaked at 30-50 nm and ranges from 10 nm to 80 nm. 57 Fe Mossbauer spectra recorded at various temperatures (5 K-300 K) in presence of external magnetic field (at 5 K) have suggested the presence of different phases of iron oxide with sizable amounts of gamma-Fe2O3 and alpha-Fe2O3 in addition to Fe3O4. The relative concentrations of these phases have been obtained by a self consistent spectral area analysis and were found to be 44:22:34 (%). (C) 2007 Elsevier Inc. All rights reserved.</p>10airon oxides10aMossbauer spectroscopy10aphase analysis10aplasma synthesis1 aNagar, Harshada1 aKulkarni, Naveen, V.1 aKarmakar, Soumen1 aSahoo, B.1 aBanerjee, Indrani1 aChaudhari, P., S.1 aPasricha, R.1 aDas, A., K.1 aBhoraskar, S., V.1 aDate, Sadgopal, K.1 aKeune, W.  uhttps://library.ncl.res.in/content/mossbauer-spectroscopic-investigations-nanophase-iron-oxides-synthesized-thermal-plasma-0