Magnetic materials nanostructures

Oliveira, F.C.C.Theuse of ionic liquids in the synthesis of nanostructured magnetic materials (translated from Portuguese), thesis, Universidade de Brasilia. (2010). 

There is considerable interest in developing new types of magnetic materials, with a particular hope that ferroelectric solids and polymers can be constructed— materials having spontaneous electric polarization that can be reversed by an electric field. Such materials could lead to new low-cost memory devices for computers. The fine control of dispersed magnetic nanostructures will take the storage and tunability of magnetic media to new levels, and novel tunneling microscopy approaches allow measurement of microscopic hysteresis effects in iron nanowires. 

The broad variety of magnetic nanostructures corresponds to a diverse range of processing methods. The suitability of individual methods depends on the length scale and geometry of the nanostructures. In addition, each method is usually restricted to a relatively narrow class of magnetic materials. 

In the section 2 of this chapter, an introduction is given to the main concepts required for the understanding of coercivity in hard magnetic materials. The various types of hard nanostructures and the procedures used for their preparation are described in section 3. The specific properties of hard nanostructure magnetism are described in section 4. In section 5, the properties of industrial materials are presented and some applications are briefly summarised. 

Abstract The focus of this chapter is primarily directed towards nanocrystalline soft magnetic materials prepared by crystallization of amorphous precursors. The key elements involved in the development of this class of materials are three-fold (i) theoretical models for magnetic softness in nanostructures (ii) nanostructure-property relationships and (iii) nanostructural formation mechanisms. This chapter surveys recent research on these three areas with emphasis placed on the principles underlying alloy design in soft magnetic nanostructures. 

The behavior of magnetic nanostructures reflects both nanoscale features, such as particle size and geometry, and the intrinsic properties of the magnetic substances. For example, the magnetization reversal in nanodots crucially depends on the anisotropy of the dot material. Furthermore, nanostructures are often used as bulk materials, so that their extrinsic properties must be evaluated from the point of view of bulk materials. This appendix summarizes the characteristics of some important classes of magnetic materials and provides exemplary data. 

In Science and Technology of Nanostructured Magnetic Materials. Eds. G. C. Hadjipanayis and G. A. Prinz. NATO ASI Series B Physics, Vol. 259. 

Krishnan, R., Lassri, H. Rougier, P. (1987). Magnetic properties of amorphous FeErBSi ribbons. Journal of Applied Physics, 62, 3463-4. Krishnan, R., Porte, M., Tessier, M. Flevaris, N. K. (1991). Structural and magnetic studies in Co-Pt multilayers. In Science and Technology of Nanostructured Magnetic Materials. Eds. G. C. Hadjipanayis and G. A. 

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