Binary magnetic moment

Fig. 3.6. Curie temperature Tc ( ) and the spontaneous magnetic moment ps (a) versus valence-electron concentration for several binary and pseudo-binary UT compounds. Data taken from Brandle et al.

EPR measurements show the existence of paramagnetic clusters, magnetic susceptibility data reveal magnetic moments indicative of fewer than one unpaired electron per cluster. Nine-atom 9" clusters also occur in binary phases, but tetrahedral four-atom 4 clusters are predominant beside the arachno-typs 5 clusters. 

In the reduced binary and ternary halides of the lanthanoids, the f electrons are well localized on the metal atoms. The coupling between the magnetic moments is weak in the case of insulators as can be seen from the low ordering temperatures of the saltlike trihalides whereby, for example, GdQj orders ferromagneti-cally at 2.2K. In the presence of extended M-M bonding, the conduction electrons provide a very efficient mechanism for coupling the moments via a RKKY... 

Fig. i. .3-1a,b Bethe-Slater-Pauling relation indicating the dependence of the mean magnetic moment per atom Pat on the average number of 3d and 4s electrons per atom for binary alloys with (a) fee stmeture and (b) bcc structure [3.6]... 

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