Results 181 to 190 of about 35,935 (220)

Spin-canting and transverse relaxation in maghemite nanoparticles and in tin-doped maghemite

Journal of Magnetism and Magnetic Materials, 2006
Abstract The magnetic properties of maghemite nanoparticles and tin-doped maghemite have been studied by 57 Fe and 119 Sn Mossbauer spectroscopy at temperatures from 6 to 300 K with and without applied magnetic fields. The low-temperature 57 Fe spectra of both samples, obtained in a field of 4 T, can be described in terms of A-site and B-site ...
Örn Helgason, Helge K. Rasmussen, Steen Mørup   +2 more
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Maghemite Nanoparticles by View of Mossbauer Spectroscopy

ChemInform, 2006
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Jirí, Tucek, Radek, Zboril, Dimitris, Petridis   +2 more
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Maghemite in Icelandic basalts

Mineralogical Magazine, 1992
AbstractCurie temperatures indicating non-titaniferous magnetite are common in Icelandic basalts of all ages, especially Tertiary ones. Yet, microprobe analyses of such samples have shown high titanium in the magnetite. To resolve this paradox, and the mechanism at work, the magnetic mineral fraction of eight basalt samples with Js-T curves ...
S. Steinthorsson, Ö. Helgason, M. B. Madsen, C. Bender Koch, M. D. Bentzon, S. Mørup   +5 more
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Photoacoustic investigation of maghemite-based nanocomposite

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
Photoacoustic spectroscopy was used to investigate magnetic nanocomposites incorporating nanosized maghemite particles into styrene-divinylbenzene copolymer template. Typical photoacoustic features were observed in bands C, S and L in the wavelength region of 300-1000 nm.
A F R, Rodriguez, M F S, Gilhermitti, F S E D V, Faria, R M, Cunha, J G, Santos, A C, Oliveira, M A, Morales, D, Rabelo, R B, Azevedo, P C, Morais   +9 more
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Variable-Temperature Mössbauer Spectroscopy of Nano-Sized Maghemite and Al-Substituted Maghemites

Clays and Clay Minerals, 1995
AbstractSynthetic aluminum-substituted maghemite samples, γ-(Fe1-xAlx)2O3, have been prepared by thermal decomposition of Al-lepidocrocite (γ-Fe1-xAlxOOH), with × = 0, 0.04, 0.06, 0.14 and 0.18. The particles are needle-shaped and the mean crystallite diameter along the [311] crystallographic direction was found to be between 2.0 and 5.0 nm.
G. M. Da Costa, E. De Grave, L. H. Bowen, P. M. A. De Barker, R. E. Vandenberghe   +4 more
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Spin frustration in maghemite nanoparticles

Solid State Communications, 2001
Abstract A different degree of internal structural disorder is observed in almost identical and uniform γ-Fe2O3 nanoparticles of about 3.5±0.6 nm, prepared by laser pyrolysis, by high-resolution transmission electron microscopy (HRTEM) and Mossbauer spectroscopy.
C.J. Serna, F. Bødker, S. Mørup, M.P. Morales, F. Sandiumenge, S. Veintemillas-Verdaguer   +5 more
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Magnetic properties of maghemite nanoparticles

Bulletin of the Russian Academy of Sciences: Physics, 2014
Magnetic particles of maghemite (spinel γ-Fe2O3) are synthesized by means of aerosol pyrolysis, making it possible to produce chemically uniform highly-dispersed single-phase materials. The magnetic properties of synthesized particles for temperatures ranging from helium temperature up to room temperature and higher are investigated using a SQUID ...
V. N. Nikiforov, A. E. Goldt, E. A. Gudilin, V. G. Sredin, V. Yu. Irhin   +4 more
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Maghemite in soils and its origin

Clay Minerals, 1974
AbstractThe products of air oxidation of mixed Fe(II)-Fe(III) chloride solutions at pH 6 and 7, at 20 and 60°C and at normal pressure contain green rust, maghemite, lepidocrocite, goethite and a paracrystalline ferric hydroxide (ferrihydrite). Among these maghemite, a cubic ferromagnetic iron oxide (Fe2O3) found in many soils, is favoured by slow ...
R. M. Taylor, U. Schwertmann
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Mössbauer study of maghemite nanoparticles

Technical Physics Letters, 2012
Mossbauer spectroscopy has been used to study maghemite (γ-Fe2O3) particles with average dimensions on the microscopic (∼1 μm, “bulk” state) and nanoscopic (15 and 20 nm) levels. Data provided by this method on the thickness of a surface region of magnetic nanoparticles and features of their magnetic state have been analyzed.
I. N. Zakharova, M. A. Shipilin, V. P. Alekseev, A. M. Shipilin   +3 more
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Synthesis and characterization of maghemite nanosheets

Materials Letters, 2011
Abstract Magnetic maghemite nanoparticles in the form of nanosheets were prepared by a topotactic transformation during the dehydroxylation of a γ-FeO(OH) precursor. The precursor was synthesized from tetrapyridin Fe(II) chloride (Fe(py) 4 Cl 2 ). The nanosheets are several hundreds of nanometers wide, and less than 5 nm thick; they frequently bend ...
Miha Drofenik, Gregor Ferk, Matjaž Kristl, Darko Makovec   +3 more
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