ZnFe2O4 nanoparticles dispersed in a highly porous silica aerogel matrix: A magnetic study

Bullita, S. and Casu, A. and Casula, M.F. and Concas, G. and Congiu, F. and Corrias, A. and Falqui, A. and Loche, D. and Marras, C. (2014) ZnFe2O4 nanoparticles dispersed in a highly porous silica aerogel matrix: A magnetic study. Physical Chemistry Chemical Physics, 16 (10). pp. 4843-4852. ISSN 1463-9076. (doi:https://doi.org/10.1039/c3cp54291b) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1039/c3cp54291b

Abstract

We report the detailed structural characterization and magnetic investigation of nanocrystalline zinc ferrite nanoparticles supported on a silica aerogel porous matrix which differ in size (in the range 4-11 nm) and the inversion degree (from 0.4 to 0.2) as compared to bulk zinc ferrite which has a normal spinel structure. The samples were investigated by zero-field-cooling- field-cooling, thermo-remnant DC magnetization measurements, AC magnetization investigation and Mössbauer spectroscopy. The nanocomposites are superparamagnetic at room temperature; the temperature of the superparamagnetic transition in the samples decreases with the particle size and therefore it is mainly determined by the inversion degree rather than by the particle size, which would give an opposite effect on the blocking temperature. The contribution of particle interaction to the magnetic behavior of the nanocomposites decreases significantly in the sample with the largest particle size. The values of the anisotropy constant give evidence that the anisotropy constant decreases upon increasing the particle size of the samples. All these results clearly indicate that, even when dispersed with low concentration in a non-magnetic and highly porous and insulating matrix, the zinc ferrite nanoparticles show a magnetic behavior similar to that displayed when they are unsupported or dispersed in a similar but denser matrix, and with higher loading. The effective anisotropy measured for our samples appears to be systematically higher than that measured for supported zinc ferrite nanoparticles of similar size, indicating that this effect probably occurs as a consequence of the high inversion degree. © 2014 the Owner Societies.

Item Type: Article
Subjects: Q Science > QC Physics > QC176.8.N35 Nanoscience, nanotechnology
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Anna Corrias
Date Deposited: 15 Dec 2014 17:05 UTC
Last Modified: 04 Dec 2017 12:19 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46141 (The current URI for this page, for reference purposes)
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