Hard-magnetic nanostructures

The study of these systems have become possible thanks to the development of various preparation routes, from sophisticated routes for the preparation of model materials with controlled nanostructures to industrial routes for the production of large quantity of materials. It has benefited as well from the development of new experimental techniques, allowing the properties of matter to be quantitatively examined at the nanometre scale. These include Hall micro-probe [3] or micro-SQUID magnetometry [4], XMCD at synchrotron radiation facilities [5] and scanning probe microscopes [6]. This is not the topic of this chapter to describe in detail these various techniques. They are only quoted in the following sections. The reader may find in the associated references the detailed technical descriptions that he may need. 

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Hard-Magnetic Nanostructures 3.3.3. FePt-hased nanocomposites... 

The original magnetic properties of hard nanostructures, described in the above sections, are direct consequences of the crystallite particle size reduction, when this size approaches the domain wall thickness, S. In this section, we apply and extend the findings of Chapters 3 and 4 to hard-magnetic nanostructures. We discuss (i) systems of exchange decoupled particles, and (ii) systems of exchange-coupled particles, themselves divided into single-phase systems and nanocomposites. 

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