Magnetic moment orbital contribution

The problem could be stated from another point of view. In an isostructural series the uranium and neptunium compounds tend to be itinerant electron magnets or band magnets (like iron) and their orbital contribution is at least partially quenched. For much heavier actinides we know that the compounds will make local moment magnets with orbital contributions. It is quite possible that in between these two clear cut forms of magnetism that the intermediate case could be dominated by fluctuations, and no recognizable form of magnetism would occur. To state that the... 

Fe " complexes in general have magnetic moments at room temperature which are close to 5.92 BM if they are high-spin and somewhat in excess of 2BM (due to orbital contribution) if they are low-spin. A number of complexes, however, were prepared in 1931 by L. Cambi and found to have moments intermediate between these extremes. They are the iron(lll)-A,A-dialkyldithiocarbamates, [Fe(S2CNR2)3], in which the ligands are ... 

Eg term. A magnetic moment of around 5.5 BM (i.e. 4.90 BM- -orbital contribution) is expected for pure octahedral symmetry but, in practice, distortions produce values in the range 5.2-5.4BM. Similarly, in the electronic spectrum, the expected single band due to the Eg t ge g) T2g t ge ) transition is broadened... 

The T ground term of the tetrahedral ion is expected to lead to a temperature-dependent orbital contribution to the magnetic moment, whereas the A ground term of the octahedral ion is not, though mixing of the excited T2g(F) term into the AigiF) ground term is expected to raise its moment to ... 

As seen in Fig. 8 the experimentally determined magnetic moments at room temperature are in general much lower than the free ion values. To extract the contribution of orbital reduction, the influence of intermediate coupling, crystal field effects and j-j mixing must be considered. 

But similar calculations for the iron-group ions show marked disagreement with experiment, and many attempts were made to explain the discrepancies. The explanation is simple in many condensed systems the perturbing effect of the atoms or molecules surrounding a magnetic atom destroys the contribution of the orbital momentum to the magnetic moment, which is produced entirely by the spin moments of unpaired electrons.40... 

For the cubic-field (octahedral or tetrahedral) subshells g(g), there is spatial degeneracy for e(g) but not for eQy Nevertheless, neither of these configurations give rise to an orbital contribution to the magnetic moment. The conditions for orbital contributions to arise in strong-field configurations are that the orbitals must be... 

In this paper, we report MCP of Use and UTe which have been carried out at AR-NE1 station of KEK, Japan, and try to separate the spin and orbital contributions of magnetic moments by combining MCP with the magnetization measurement. Furthermore, we discuss the degree of localization of 5f electrons of these samples by decomposing the MCP into localized component and itinerant component. 

The orbital contribution pL has been deduced by combining spin moments ps (all) by the MCP with the magnetization measurement M by an equation pL = ps (all) - M. 

The spin moments were decomposed into localized 5f component, ps(5f), and diffused components, ps(diff). Combining magnetization measurement with this decomposition, the orbital contribution, pL(5f), has been deduced. ... 

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