Magnetism of Low-Dimension Alloys

Abstract

The magnetic properties of metals are very sensitive to the size of the objects, to their organization when non-isolated, as well as to their chemical content and order when alloyed. In this chapter, first we go through the different magnetic energies in competition and the different length scales of importance in the magnetic behaviour and configurations of objects. Different magnetic properties of materials are then described: magnetic ordering and Curie temperature, magnetization reversal and hysteresis loops, the different contributions of the magnetic anisotropy, the thermal stability and superparamagnetism, and finally the effects of nanometric size and of alloying and chemical order on magnetic properties… We thus describe different magnetic properties in pure metals, as well as their modifications due to the effects of surface vicinity, size reduction, interface presence, and alloying. Finally the most classical experimental means will be scanned to allow the reader an enlightened choice when confronted with the magnetism of nanoalloys. This subject is very wide and several books have been recently written on the magnetism of nano-objects [1, 2], the scope of this chapter is thus in no case to be exhaustive, but to give to the reader a first idea of the effects of size and alloying on magnetism of nanoalloys. The results in nanoalloys are today quite scarce because the subject is new and very difficult.