Title: Structure and magnetic properties of nano-sized HoFe₂O₄ material

Authors: A. Jaafar, A. Al-Saie, M. Bououdina

Addresses: Department of Physics, College of Science, University of Bahrain, Sakhir Campus, P.O. Box 32038, Kingdom of Bahrain. ' Nanotechnology Centre, University of Bahrain, Sakhir Campus, P.O. Box 32038, Kingdom of Bahrain; Department of Physics, College of Science, University of Bahrain, Sakhir Campus, P.O. Box 32038, Kingdom of Bahrain. ' Nanotechnology Centre, University of Bahrain, Sakhir Campus, P.O. Box 32038, Kingdom of Bahrain; Department of Physics, College of Science, University of Bahrain, Sakhir Campus, P.O. Box 32038, Kingdom of Bahrain

Abstract: A mixture of Ho₂O₃ and Fe₂O₃ were mechanically alloyed followed by subsequent annealing to produce a single nanocrystalline HoFe₂O₄ phase. XRD patterns and magnetisation hysteresis curves were obtained for both the as-milled and annealed samples. XRD analysis indicates the formation of an initial amorphous phase in the as-milled powder. After annealing up to 1200°C, the material crystallises into nanosized (75 nm) monoferrite HoFe₂O₄ phase, accompanied by dramatic increment of magnetic properties. Moreover, the HoFe₂O₄ shows a ferromagnetic behaviour and a large hysteresis loop with Ms ≈ 72 emu/g, Hc ≈ 1.4 kOe and Mr ≈ 39 emu/g.

Keywords: spinel ferrite; holmium; mechanical alloying; nanoparticles; magnetic properties; X-ray diffraction; nanocrystals; nanotechnology; annealing; nanostructure.

DOI: 10.1504/IJNP.2010.034850

International Journal of Nanoparticles, 2010 Vol.3 No.2, pp.173 - 178

Published online: 25 Aug 2010 *

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