Magnetic polarisability

L.T. Muus, P.W. Atkins, K.A. McLauchlan and J.B, Pedersen (Eds.), Chemically Induced Magnetic Polarisation, Reidel, Dordrecht, 1977. 

Despite their long pedigree, however, the ewent interest in the Heusler and semi-Heusler alloys was only sparked in 1983 upon the publication of a theoretical paper by de Groot et al [125] in which the prototypical semi-Heusler alloy NiMnSb was predicted to display half-metallic properties. The concept of a half-metal needs to be carefully distinguished from the similar-sounding but entirely different conc ts of Ae semi-metal and the semiconductor. The property of half-metallicity is inextricably linked with the permanent magnetic polarisation of a material, and refers to the case when the electrons at the Fermi level display 100% spin-polarisation. In other words, while the electronic bands of one spin-species cross the Fermi level, those of the other spin-species do not. In the case of half-metallic semi-Heusler alloys, the majority-spin electrons behave as if the material were a good metal, while the minority-spin electrons behave as if the material were an insulator or semiconductor. 

The required magnetic polarisation can be achieved at a temperature that is not... 

Clol Closs, G.L. Chemically Induced Magnetic Polarisation A.R. Leplcy and G.L. Closs, Eds. New York Wiley 1973, 95. 

To appreciate the significance of these numerous orda parameters it is helpful to see how they are related to the anisotropic properties of a nematic. As an example we consider the anisotropy in the magnetic susceptibility. Ax, as we have for previous systems. The starting point is the magnetic polarisability expressed in a molecular frame s in a rigid fragment of the molecule. This tensor K ( ends, in genaal, on the conformation of the molecule, a fact which we have... 

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