Tanwar, Sanju and Awana, V. P. S. and Singh, Surinder P. and Pasricha, Renu (2012) Magnetic Field Dependence of Blocking Temperature in Oleic Acid Functionalized Iron Oxide Nanoparticles. Journal of Superconductivity and Novel Magnetism, 25 (6). pp. 2041-2045. ISSN 1557-1939

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Abstract

We report the synthesis of phase pure, monodispersed Fe3O4 nanoparticles of size similar to 10 nm via chemical co-precipitation of ferrous and ferric ions, under controlled pH and temperature. The nanoparticles are oleic acid functionalized and hence dispersible in organic medium. The structure and morphology of nanoparticles are determined by analyzing XRD pattern and TEM micrographs, confirming the formation of phase pure Fe3O4 nanoparticles. The magnetization studies reveal the superparamagnetic behavior of the nanoparticles at room temperature. The changes in blocking temperatures (T-B) of magnetic nanoparticles with applied magnetic fields (H-ap), noted from the cusp of the zero-field-cooled magnetization, the indicate effects of dipole interactions. A decrease in blocking temperature from 95 K to 15 K has been observed on varying the magnetic field from 50 Oe to 5000 Oe. T-B versus H relation follows the equation T-B(H) = T-o(1 - (H/H-o))(m), i.e. the Neel-Brown model of magnetic relaxation in nanoparticles.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s Springer Verlag.
Subjects:	Applied Physics/Condensed Matter
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	13 Mar 2020 11:32
Last Modified:	13 Mar 2020 11:32
URI:	http://npl.csircentral.net/id/eprint/3507

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