Magnetic chains specific heat

D correlations have been detected above TN by neutron diffraction, specific heat and NMR measurements mostly by Hirakawa and coworkers64 705. Magnetic susceptibility results have also been interpreted in terms of short-range couplings of a chain model on the basis of the calculations of Bonner and Fisher and of Oguchi. The main interaction occurs along the c-axis with J/k = —190 K. 

Figure 12-2 (a) Specific heat (A) and viscosity (B) of liquid sulfur, (b) Chain length (P) as a function of temperature, X from magnetic susceptibility measurements and from esr measurements. 

The uniform Heisenberg magnetic chain has been an object of study for three quarters of a century, dating back to the initial work of Bethe. Unhke the equivalent Ising and XY-chains, the Heisenberg model cannot be solved analytically. The first calculations of the susceptibihty and specific heat... 

The low-temperature (10 mK < T < 20 K) thermodynamics of quinolinium (TCNQ)2 are now rather well represented by random-exchange Heisenberg anti-ferromagnetic chains (REHACs). While MP-TCNQ has similar power laws , its magnetic specific heat is quite different possibly due to facile methyl rotation about the 6-fold MP barrier . Disorder is surely important, but MP-TCNQ is complicated in this respect also. 

The smearing of the superconducting transition may be caused by localized magnetic moments at the ends of broken (SN)x chains, by other sample inhomogeneities or by fluctuation effects. The specific heat anomaly is... 

Fig. 58. (a) Specific heats of Gd2Cl3 and YjClj (full line) the arrow indicates the 3D ordering transition, (b) Magnetic part of the specific heat of Gd Clj (per formula unit GdCl, 5) the full line is the specific heat of an S — j Heisenberg chain with exchange constant J = — 2.6 K (after Kremer 1985). 

SPECIFIC HEAT OF THREE MAGNETIC LINEAR-CHAIN ANTIFERROMAGNETS. 

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