Conduction electron spin polarization

As is evident from a comparison of eqs. (lid) and (lie), there is also a direct empirical access to the conduction electron spin polarization, if magnetic ordering temperatures and transferred hyperfine fields at the R site are compared. Both quantities contain the spin polarization at the R site, induced by all the other R electronic spins... 

The magnetic interaction between the ions in the magnetic metals for example, can then be considered as carried by the conduction electrons in the well known Rudermann-Kittel-Kasuya-Yoshida (1 ) interaction. The physical origin of this interaction is a point like polarization of the conduction electrons (CE), at the atomic sites, by the magnetic moments of the f electrons, resulting in an oscillation of the spin density of the CE. The point like approximation is useful because the maxima of the f wave functions are found well inside the atomic core, in radii smaller than 0.7 atomic units. This polarization is carried from ion to ion by the generated polarization oscillation of the conduction electron spins, which has a wave length = 27r/e (C =... 

The main motivation of the spin polarized band calculation was to study the spatial distribution or form factor of the conduction electron spin. This will be discussed more thoroughly in ch. 7, section 4. 

In the RKKY interaction, a localized spin S,- interacts with a conduction electron with spin s, which leads to a spin polarization of the conduction electron. This polarization interacts with another spin 5) localized on ion j and therefore creates an indirect interaction between the spins St and Sj. This indirect interaction extends to the far distance and damps with a sinusoidal 2k oscillation, where kf is half of the caliper dimension of the Fermi surface. When the number of 4f electrons increases in such a way that the lanthanide element changes from Ce to Gd or reversely from Yb to Gd in the compound, the magnetic moment becomes larger and the RKKY interaction stronger, leading to... 

As already proposed by Albert Overhauser [203] in 1953 and subsequently confirmed experimentally by Carver and Slichter [204, 205], electron spin polarization in solid metals can be transferred to nuclear spins if the unpaired conducting electrons are saturated by irradiation with the corresponding electron paramagnetic resonance (EPR) frequency. As a result, nuclear spin polarization may be enhanced by the factor yJyt,. Likewise, stable organic radicals can be used as polarizing agents. 

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