Preparation and Characterization of Nano-Sized Magnesium Ferrite Powders By a Starch-Gel Process and Corresponding Ceramics

Journal of Material Science (2013) 48:6509–6518

29 Pages Posted: 10 Jul 2018

See all articles by Roberto Köferstein

Roberto Köferstein

Martin Luther Universitat Halle Wittenberg

Till Walther

Martin Luther University of Halle-Wittenberg - Institute of Chemistry, Inorganic Chemistry

Dietrich Hesse

Max Planck Institute of Microstructure Physics

Stefan Ebbinghaus

Martin Luther University of Halle-Wittenberg - Institute of Chemistry, Inorganic Chemistry

Date Written: October 2, 2013

Abstract

The synthesis and characterization of nano-sized MgFe2O4 by a starch-gel method is described herein. A phase-pure nano-sized MgFe2O4 powder (1a) was obtained after calcining a (MgFe) starch gel at 550 °C. The powder has a specific surface area of 60.6 m2/g and a crystallite size of 9 nm. TEM investigations reveal particles in the range of 7 to 15 nm. The activation energy of the crystallite growth process was calculated as 89 ± 14 kJ/mol. The shrinkage and sintering behaviour of resulting compacts were studied. UV−VIS investigations of the nano-sized powder 1a reveal an optical band gap of 2.38 eV, whereas calcination at 1100 °C (powder 1g) leads to a crystallite size of 129 nm and a band gap of 2.16 eV. Magnetization loops at 300 K and the temperature dependence of both the field-cooled (FC) and the zero-field-cooled (ZFC) agnetization indicate a superparamagnetic behaviour. The blocking temperature for powder 1a was determined as 140 K at a field of H = 500 Oe. We found different saturation magnetizations (Ms) depending on the calcination temperature. Calcination at 550 °C (1a) results in Ms = 20.0 emu/g which increases with calcination temperature to a maximum of 37.7 emu/g for powder 1e calcined at 900 °C. Ceramic bodies sintered between 1450 and 1600 °C exhibit Ms values of 25−28 emu/g. Magnetic investigations at 10 K on powders 1a−1g show hysteresis loops with coercivities up to 950 Oe, remanences to 10 emu/g and Ms values to 50.4 emu/g. Additionally, the nano-scaled powders show a shift of the hysteresis loops.

Suggested Citation

Köferstein, Roberto and Walther, Till and Hesse, Dietrich and Ebbinghaus, Stefan, Preparation and Characterization of Nano-Sized Magnesium Ferrite Powders By a Starch-Gel Process and Corresponding Ceramics (October 2, 2013). Journal of Material Science (2013) 48:6509–6518, Available at SSRN: https://ssrn.com/abstract=3206736 or http://dx.doi.org/10.2139/ssrn.3206736

Roberto Köferstein (Contact Author)

Martin Luther Universitat Halle Wittenberg ( email )

Universitätsplatz 10
Halle (Saale), Saxony-Anhalt 06108
Germany

Till Walther

Martin Luther University of Halle-Wittenberg - Institute of Chemistry, Inorganic Chemistry

Halle (Saale), Saxony-Anhalt 06108
Germany

Dietrich Hesse

Max Planck Institute of Microstructure Physics

Weinberg 2
06120 Halle (Saale)
Germany

Stefan Ebbinghaus

Martin Luther University of Halle-Wittenberg - Institute of Chemistry, Inorganic Chemistry ( email )

Halle (Saale), Saxony-Anhalt 06108
Germany

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