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Superparamagnetic behaviour and T-1, T-2 relaxivity of ZnFe2O4 nanoparticles for magnetic resonance imaging

Hoque, Manjura S and Srivastava, C and Venkatesha, N and Anil Kumar, PS and Chattopadhyay, K (2013) Superparamagnetic behaviour and T-1, T-2 relaxivity of ZnFe2O4 nanoparticles for magnetic resonance imaging. In: Philosophical Magazine, 93 (14). pp. 1771-1783.

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Official URL: http://dx.doi.org/10.1080/14786435.2012.755271


In the present study, ZnFe2O4 nanoparticles were synthesized by the chemical co-precipitation followed by calcinations at 473 and 673K for 4h. Particle sizes obtained were 4 and 6nm for the calcination temperatures of 473 and 673K, respectively. To study the origin of system's low temperature spin dynamic behaviour, temperature dependence of susceptibility was investigated as a function of particle size and frequency. Slight increase in the grain size from 4nm at 473K to 6nm at 673K has led to a peak shift of temperature dependence of susceptibility measured at a constant frequency of 400Hz. Temperature dependence of at different frequencies also resulted in peak shift. Relaxation time dependence of peak temperature obeys a power law, which provides the fitting parameters within the range of superparamagnetic nature of the particles. Further, dependence of relaxation time and peak temperature obeys VogelFulcher law rather than NeelBrown equation demonstrating that the particles follow the behaviour of superparamagnetism of slightly interacting system. Spinlattice, T-1 and spinspin, T-2 relaxivity of proton of the water molecule in the presence of chitosan-coated superparamagnetic ZnFe2O4 nanoparticle yields the values of 0.002 and 0.360s(1)perppm.

Item Type: Journal Article
Publication: Philosophical Magazine
Publisher: Taylor and Francis Group
Additional Information: Copyright of this article belongs to Taylor and Francis Group.
Keywords: ZnFe2O4; Superparamagnetism; T; (1) and T; (2) Relaxivity; Nuclear Magnetic Resonance; Transmission Electron Microscopy
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 05 Jul 2013 06:04
Last Modified: 05 Jul 2013 06:04
URI: http://eprints.iisc.ac.in/id/eprint/46797

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