Structural, magnetic and Mossbauer studies on nickel-zinc ferrites synthesized via a precipitation route

Date, SK and Joy, PA and Kumar, Anil PS and Sahoo, B and Keune, W (2004) Structural, magnetic and Mossbauer studies on nickel-zinc ferrites synthesized via a precipitation route. In: Physics State of Solids (C), 1 (12). pp. 3495-3498.

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Abstract

Polycrystalline Ni-Zn ferrite, with a well-defined composition, $Ni_{0.8}Zn_{0.2}Fe_{2}O_4$, synthesized by a low temperature method showed the formation of a cubic ferrite phase with a crystallite size of 15 nm and saturation magnetization of Ms ≈ 44 emu/g at room temperature. When calcined at higher temperatures (up to 1200 oC) the magnetization increased continuously to Ms ≈ 67 emu/g. To understand the magnetic nature of the cubic ferrite phase formed at a temperature as low as 80 oC, 57 Fe Mossbauer spectra were recorded for samples annealed at three different temperatures, without any external magnetic field, and with an external field of $H_ext$ = 5 T, at 4.2 K. The spectral parameters at room temperature, namely, isomer shift, quadrupole splitting and hyperfine field, confirmed the presence of ultrafine superparamagnetic crystallites of Ni-Zn ferrite. The Mössbauer spectra at 4.2 K revealed spin relaxation effects resulting in very broad sextets, characteristic of ultrafine crystallites. The Mössbauer spectra recorded at 4.2 K and $H_ext$ = 5 T showed well resolved two sextet pattern with characteristic hyperfine interaction parameters of the cubic ferrite phase.

Item Type:	Journal Article
Publication:	Physics State of Solids (C)
Publisher:	WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Additional Information:	The copyright belongs to WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Keywords:	polycrystalline;nickel zinc ferrites;synthesis
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	04 Oct 2005
Last Modified:	19 Sep 2010 04:20
URI:	http://eprints.iisc.ac.in/id/eprint/3758

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