Preparation and Properties of Iron and Iron Oxide Nanocrystals in MgO Matrix

Abstract

We have prepared α-iron and magnetite (Fe 3 O 4 ) nanoparticles in MgO matrix from a mixture of nanocrystalline Fe 2 O 3 with Mg(H,O) powders calcinated in hydrogen. This procedure yielded spherical magnetic nanoparticles embedded in MgO. Transmission electron microscopy and Mössbauer spectroscopy were used for structure and phase analysis. The measurements of magnetic properties showed increased coercivity of the nanocomposite samples.

Ultrathin MgO Coating of Superparamagnetic Magnetite Nanoparticles by Combined Coprecipitation and Sol–Gel Synthesis

“…1,7 For instance, the physical properties of magnesium oxide (MgO), that is, low specific weight, high temperature stability because of its high melting point, 9 and negligible lattice mismatch with the magnetite, 10 make it a very promising coating material to achieve a good protection of the magnetic core. 11 Inorganic coatings as silica and magnesium oxide are also used as dielectric layer to isolate magnetic nanoparticles in composites for high-frequency electronic applications. It is well established that, to meet the high permeability requirements, the coating has to be thin compared with the particle size.…”

“…Although organic coatings are often used to prevent particle aggregation by passivating the iron oxide surface, and therefore enhancing the particle stability, the use of inorganic materials offers a better protection of the magnetic core from its oxidation. , For instance, the physical properties of magnesium oxide (MgO), that is, low specific weight, high temperature stability because of its high melting point, and negligible lattice mismatch with the magnetite, make it a very promising coating material to achieve a good protection of the magnetic core . Inorganic coatings as silica and magnesium oxide are also used as dielectric layer to isolate magnetic nanoparticles in composites for high-frequency electronic applications.…”