ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Magnetic properties of binary and ternary mixed metal oxides NiFe2O4 and Zn0.5Ni0.5Fe2O4 doped with rare earths by sol—gel synthesis
Martin Tsvetkov, Maria Milanova, Laura C. J. Pereira, João C. Waerenborgh, Zara Cherkezova-Zheleva, Joana Zaharieva, and Ivan Mitov
Department of Inorganic Chemistry, Faculty of Chemistry and Pharmacy, Sofia University “St. Kliment Ohridski”, 1, J. Bourchier, 1164 Sofia, Bulgaria
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Abstract: The spinel-type ferrites NiFe2O4 and Zn0.5Ni0.5Fe2O4 modified by lanthanide ions Eu3+ and Tb3+ were prepared by a sol-gel process with propylene oxide as a gelating agent. The phase homogeneity of the samples was tested by XRD and Mössbauer spectroscopy. Transmission electronic microscopy used for characterisation of the morphology of the samples revealed nanosized powdered samples with a narrow distribution of particle sizes. It was noted that the presence of Ln3+ ions influenced the magnetic properties of nanosized NiFe2O4 and Ni0.5Zn0.5Fe2O4 ferrites. The dependence of the magnetic properties of the samples on the rare-earth doping may be explained by the different grain sizes. The saturation magnetisation tends to decrease with increasing rare-earth doping and decreasing crystallite size. A similar trend was observed for the coercive field, with the exception of the Tb3+ -doped Zn0.5Ni0.5Fe2O4 where it remained the same as in the pure ferrite.
Keywords: ferrites; lanthanides; Mossbauer spectroscopy; XRD; magnetic properties
Full paper is available at www.springerlink.com.
Chemical Papers 70 (12) 1600–1610 (2016)
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