Magnetic susceptibility various materials

Table 19-16 shows the magnetic susceptibility of minerals and elements. Magnetization of various materials is directly dependent on... 

Fig. 10. Temperature dependence of the magnetic susceptibility of various carbon-based materials. The data on HOPG (H//c) are taken at 200 Oe. The data reported for nanolubes, graphite (H in-plane), and diamond, were taken at 4 kOe, those on diamond at 8 kOe. The ordinate axis is negative (after Heremans et al.[26 ).

PBLG is a para-magnetic material with positive magnetic susceptibility anisotropy ya. It exhibits the cholesteric phase in various solutions with a helical pitch ranging from ten to tens of microns. The unwinding effect is an approach to measure the twist elastic constant K22-... 

Many of the blues mentioned in Section 5.2 have been characterized by UV/visible and EPR spectroscopy, and clearly the oligomeric nature of these species warns against any comparisons with the discrete blues discussed above. The isolation of the crystalline blue materials (Table 5.II) has permitted various spectroscopic and theoretical studies to elucidate the origin of the blue color. Magnetic susceptibility, EPR, optical and X-ray photoelectron spectroscopic parameters have all been obtained [65, 66]. The studies on the original platinum—a-pyridone blue have been supplemented by the more recent structures. 

The specific heat C T) has a linear temperature dependence for T To, peaks near To, and declines steadily at higher temperatures, as shown in fig. 22. The magnetic susceptibility x(T) is independent of T for T Tq. The susceptibility has a peak around Tq for impurity spin S>i At T Tq the quantity x(T) has a 1/T dependence as shown in fig. 23. Both results are in good accord with experimental data provided that one regards the material as a lattice of Ce or U impurities and scales up the thermodynamic quantities by the density of impurity atoms. In fig. 24 we show the magnetic field dependence of the specific heat and compare the results with the data on Ce (S = f) impurity in LaAlj (Bader et al. 1975). The predicted magnetization behavior for the same system is compared with the data at various fields and temperatures in fig. 25. The success of these and other comparisons to be discussed later are widely accepted as convincing evidence that the Kondo effect embodies the most important physics in mixed-valence and heavy-fermion systems. 

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