Magnetically non-dilute compounds

As we have seen, this relationship holds quite well for the first row transition series. For the second and third row elements it gives totally misleading results because the spin-orbit coupling of these ions is much greater than /cT—so that, usually, the plateau of the Kotani plot has not been reached. 

When a simple Curie law plot of against T (this pattern was discussed in Section 9.2) does not give a straight line it is often found that a modified form, the Curie-Weiss law, does  

Ferrimagnetism similar to antiferromagnetism except that the two sets of magnets are of different strength, leading to preservation of magnetism at low temperatures. 

The third class is that of ferrimagnetic materials. Just as for materials 

Key to the development of ferromagnetic coupling in the argument above was a step involving the orthogonality of two orbitals. The orthogonality need not be between metal and ligand orbitals. In Fig. 9.9(c) is shown an interaction pathway which includes two p orbitals on the same atom these 

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