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J Mater Sci: Mater Electron (2011) 22:10461052 DOI 10.1007/s10854-010-0257-x
Mechanosynthesis and magnetic characterization of nanocrystalline manganese ferrites
Ana M. Bolarn-Mir Pedro Vera-Serna
Flix Snchez-De Jess Claudia A. Corts-Escobedo
Antonia Martnez-Luevanos
Received: 30 September 2010 / Accepted: 13 November 2010 / Published online: 27 November 2010 Springer Science+Business Media, LLC 2010
Abstract Manganese ferrites, MnFe2O4d, synthesized via mechanosynthesis from different manganese sources,
MnO, Mn2O3 and MnO2, and mixed with Fe2O3, were studied. XRD, SEM and magnetometry were used to characterize the synthesized powders. The MnFe2O4 spinel phase appeared after 12 h of milling when MnO and MnO2 mixed with Fe2O3 were used as the precursors and showed the maximum saturation magnetization value(49.77 emu/g). Manganese ferrite did not form when MnO2 was used. Manganese ferrite obtained from Mn2O3 showed the lowest saturation magnetization value. An increase in the milling time promoted the increase in the saturation magnetization values.
1 Introduction
Spinel ferrites are important commercial ceramics. Since the 1950 s, many applications have emerged using these materials [15]. Lately, there have been changes in the development of magnetic nanomaterials that can be called revolutionary, to say the least; the changes are related both to the development of efcient methods for the preparation
and stabilization of nano-sized magnetic particles and to the progress in the physical methods for the investigation of such particles. In the past decade, various articles on their magnetic properties were written [611], and they showed the relation between the magnetic properties and particle size, shape, synthesis methods, structure, and precursor material [610].
Spinels are characterized by a compact oxygen array with cations in tetrahedral (A) and octahedral (B) coordination and may be described by the formula IV(A1-i Bi) VI(B2-i Ai)O4, where IV and VI are tetrahedrally and octahedrally coordinated sites, A and B are cations with variable valency, and i is the inversion parameter. Normal spinels have i = 0, and inverse spinels have i = 1 [12].
Manganese ferrites are used in microwave and magnetic recording applications [1315], as a precursor to Mn-Zn ferrites [16], and in bio-funtionalization [9]. These ferrites can be synthesized by several processes. The conventional and oldest one is the calcination of a mixture of oxides or carbonates in a furnace at 1,000 C [16]. This process produces large...