%0 Journal Article
%T Structure and Magnetic Properties of Aerosol Nanoparticles of Fe and Its Alloys
%A Yu. I. Petrov
%A E. A. Shafranovsky
%J International Journal of Inorganic Chemistry
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/610305
%X Structure and magnetic properties of aerosol nanoparticles of Fe and its alloys (FeMn, FeNi, FeNiMn, FePt, FeCr, FeCo, and FeCu) have been reviewed. It has been shown that, compared to a bulk material, the particles have a number of specific features being of much fundamental and applied interest. The effect of both a quenched high-temperature Fe modification and its oxides on the structure and magnetism of nanoparticles has been considered in detail. Particular attention has been paid to the recently observed fine structure in the hyperfine field distribution at iron nuclei in M£¿ssbauer spectra for pure iron and its alloys both as a bulk and aerosol nanoparticles. This phenomenon makes it possible to reveal very weak magnetic interactions in the system under study. The plausible origin of these magnetic interactions has been also discussed. 1. Introduction Nowadays investigation of the properties of Fe-based nanoparticles is of much interest from fundamental and applied standpoints [1¨C3]. These particles have high coercivity, and, according to estimates, they are single domain. Short chains of Fe particles and elongated Fe3O4 particles have long been used for magnetic recording. This is due to their high magnetic anisotropy, large magnetic moment per volume unit, and rectangular hysteresis loop. A rapidly developing nanotechnology [4] offers new applications of magnetic particles. This is, first, development of ultrahigh-density magnetic storage devices based on the giant magnetoresistance effect. Nanoparticles of metastable ball-milled Cu-rich FeCu alloys approach for this purpose. They show a giant magnetoresistance effect, which can be also used to develop sensors [5¨C8]. Second, magnetic nanoparticles can be used for drug delivery. Magnetic fine particles can act as a contrast agent for magnetic resonance imaging and can be used for cell separation and various cancer treatments. The latter may be performed, for example, by directing Fe3O4 particles to tumour sites, using a liquid suspension comprising ultrafine particles surrounded by chains of a blood-plasma substitute. Then one can induce hyperthermia in the targeted cells by a localized heating of magnetite with an RF generator. Magnetic fine particles have also been used to orient biological assemblies and to isolate red blood cells. A number of reviews on magnetic nanoparticles for applying in technology and biomedicine is growing rapidly day by day. The properties of ferromagnetic and antiferromagnetic nanoparticles applied in magnetic fluids for sealing, damping, sensing, and bearing
%U http://www.hindawi.com/journals/ijic/2012/610305/