Magnetic susceptibility Pauli paramagnetism

Electrons of the valence band, more exactly electrons in an energy interval kT near the Fermi level, bring about a specific contribution to several physical properties like electrical conductivity, specific heat, magnetic susceptibility (Pauli paramagnetism) etc. contributions which can be measured experimentally. 

To derive the magnetic susceptibility the argument then follows lines which are similar to the treatment of Pauli paramagnetism. Essentially (see Fig. 13), the two populations must have the same pp, and this causes a disequilibrium leading to a net magnetic moment (n+ - n ). The paramagnetic susceptibility is given as ... 

The magnetic susceptibility is also derived from the electron density. There are two contributions (19) the Pauli paramagnetism and the Landau diamagnetism. The former is given by... 

PrFe4Sbj2 is likely a metal. Magnetic measurements on polycrystalline samples that were about 90% phase pure indicated ferromagnetic ordering below 5 K with a moment of 1 /i per formula unit. The only other phase detected using X-ray diffraction was FeSb2, which has a weak Pauli paramagnetic susceptibility (Dannebrock et al., 1996). 

The electrical resistivity, magnetic susceptibility and magnetization for YbTSb compounds (T = Cu, Ag, Au) were measured by Katoh et al. (1997) the results are presented in table 47 and fig. 47. Also, Flandorfer et al. (1997) classified the YbCuSb and YbAgSb compounds as temperature independent Pauli-type paramagnets whereas a small magnetic moment = 1/jb was observed for YbAuSb. From X-ray absorption spectroscopy at 10 and 300 K, Yb was determined to be dipositive with temperature independent valences for all compounds 2.06 for M = Ag, 2.08 for M = Cu and 2.14 for M = Au. 

Where strong-correlation fluctuations are present in an itinerant-electron matrix, the magnetic susceptibility may be interpreted as a coexistence of Curie-Weiss and mass-enhanced Pauli paramagnetism. 

Fig. 2. Temperature dependence of the magnetic susceptibility x (right scale) and of the field for Pd NMR at fixed Larmor frequency Bo (left scale) for palladium. Similar to Fig. la, the NMR field shift and the susceptibility are proportional. Both are (mainly) caused by the Pauli-type paramagnetism of the d-like conduction electrons. (The temperature dependence is not predicted by the simple free-electron description of the susceptibility in metals.) [Reproduced with permission from Seitchik et al. (16). Copyright 1964 American Physical Society.]...

The magnetic susceptibility was found to be field independent for both CogSg and Ni3S2. This indicates the absence of any ferromagnetic impurity. In addition, the susceptibilities for both of these materials are temperature independent, and their respective values of 1.3x10 and 0.6x10" emu/g are consistent with Pauli paramagnetism. 

On the other hand, in the case of a Pauli paramagnet the magnetic susceptibility is proportional to the density of states at the Fermi level. The change of the electronic properties by alloying leads to a variation of the susceptibility. Weiqi et al. (1992) and Jianhui et al. (1992) have measured the susceptibility to observe changes in the electronic properties of Pd in Pd R/AI2O3 catalysts and to correlate them with their catalytic properties. 

The paramagnetism of the conduction electrons, not observable by ESR, can however be detected by a measurement of the magnetic susceptibility. In the region of metalhc conductivity, one observes in the contribution of the conduction electrons a nearly temperature-independent Pauli susceptibility, well known from metals. In those crystals which undergo a Peierls transition and become semiconductors or insulators at low temperatures, the Pauli susceptibility is transformed into a Curie-law behaviour. The susceptibility then increases with further decreasing tern-... 

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