Magnetism spin susceptibility

Figure 8 Temperature dependence of the magnetic spin susceptibility of members of (TMljX series. The arrows indicate the temperature scale for the onset of the insulating behavior in the resistivity for (TMTTF)2PFj and (TMTTFljBr (see Fig. 4).

Pauli spin susceptibility for the aligned CNTs has been measured and it is reported that the aligned CNTs are also metallic or semimetallic [30]. The temperature dependence of gn and gx s plotted in Fig. 5(a). Both values increase with decreasing temperature down to 40 K. A similar increase is observed for graphite. The g-value dependence on the angle 0 at 300 K is shown in Fig. 5(b) (inset). The g-value varies between gn = 2.0137 and gx= 2.0103 while the direction of magnetic fields changes from parallel to perpendicular to the tubes. These observed data fit well as... 

Temperature dependence of magnetic susceptibility of the PF6 salt was measured from 300 to 4 K at 5 T [35], The spin susceptibility of this salt gradually decreases from 300 to 50 K. Below 50 K, the susceptibility exhibits a rapid decrease accompanied by anisotropic temperature dependence, which is an indication of the long-range antiferromagnetic ordering. A one-dimensional Heisenberg model is... 

Magnetic Susceptibility of TiNi has been previously observed [39] to be temperature independent and interpreted as due to Pauli spin susceptibility. This categorizes the magnetic property as one that is insensitive to the atomic arrangement. The magnetic susceptibility has the constant values, 2.1 x 10 6 (emu/g) below the Ms and 3.0 x 10"6 (emu/g) above the As temperature. Between these two temperatures a plot of the data has a triangular form but as predicted, no difference is observed between those obtained from complete and incomplete cycles. 

To derive the dynamical spin susceptibility in the superconducting state we use the method suggested by Hubbard and Jain[15] that allows to take into account strong electronic correlations. First we add the external magnetic field applied along c-axis into the effective Hamiltonian... 

For both systems the temperature dependence of the spin susceptibility is about similar, with a 40% monotonous drop from 300 K to 50 K [37,38]. Clearly, there is no close relation between transport and magnetic properties in the high-7 regime of these salts. This is an experimental illustration of the spin-charge separation concept of one-dimensional conductors. 

The effect of anion ordering on the stability of FISDW phases has been confirmed quantitatively by calculation of the spin susceptibility following the standard approach and including an additional periodic potential with wave vector Q = (0, 5, 0) [135]. After this numerical computation even phases (N = 0, 2) are suppressed, whereas odd phases N = 1,3 are not. The same model also explains the normal-phase reentrance above 17 T. However, the predicted oscillation for Tc versus the magnetic field in the N = 0 phase is still lacking in the experimental data. 

We should mention that another possible explanation of the Pauli-like behavior has recently been proposed in terms of contributions of the triplet-excited bipolaronic states to the spin susceptibility [94]. As shown by Bussac and Zuppiroli, the polaron-bipolaron energy difference U is essentially determined by the interdopant distance Ld. The authors also consider the bipolaron triplet state, which reduces to two separate polarons for large Ld. Due to disorder, the Ld are distributed, giving rise to a distribution for the energy of the magnetic states. Summing over the distribution yields a Curie-like contribution, plus a smoothy temperature-dependent term, which resembles a Pauli contribution. 

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