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Superparamagnetic particles in ZSM-5-type ferrisilicates

Lopez, A; Lazaro, FJ; GarciaPalacios, JL; Larrea, A; Pankhurst, QA; Martinez, C; Corma, A; (1997) Superparamagnetic particles in ZSM-5-type ferrisilicates. Journal of Materials Research , 12 (6) 1519 - 1529. 10.1557/JMR.1997.0208. Green open access

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Abstract

As-synthesized, low iron content, ferrisilicates of ZSM-5-type contain well-separated Fe(III) ions in a tetrahedral environment and display paramagnetic behavior. After hydrothermal treatment, the iron ions are partially extracted from the framework, generating nanosize iron oxide or oxyhydroxide ferrimagnetic particles. This process has been studied by transmission electron microscopy (TEM), Mossbauer spectroscopy, magnetic ac susceptibility (chi(ac)), and field dependent magnetization, on samples containing up to 6.7 wt. % Fe. The experiments evidence the growth of nonaggregated particles, with a typical size around 3 nm, presumably located at the surface of the ferrisilicate crystallites, From a thorough granulometric analysis involving TEM and chi(ac) data, it is concluded that, in the range from 1.5 to 4.6 wt. % Fe, the particle size distributions are significantly independent of the iron content.

Type: Article
Title: Superparamagnetic particles in ZSM-5-type ferrisilicates
Open access status: An open access version is available from UCL Discovery
DOI: 10.1557/JMR.1997.0208
Publisher version: http://dx.doi.org/10.1557/JMR.1997.0208
Language: English
Additional information: Copyright Cambridge University Press 1997
Keywords: Mossbauer, Magnetism, Zeolite, Oxides
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng
URI: https://discovery.ucl.ac.uk/id/eprint/59477
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