Ferromagnetism near criticality

Iiifomiation about the behaviour of the 3D Ising ferromagnet near the critical point was first obtained from high- and low-temperatnre expansions. The expansion parameter in the high-temperatnre series is tanli K, and the corresponding parameter in the low-temperatnre expansion is exp(-2A ). A 2D square lattice is self-dual in the sense that the bisectors of the line joining the lattice points also fomi a square lattice and the coefficients of the two expansions, for the 2D square lattice system, are identical to within a factor of two. The singularity occurs when... 

FIRST ORDER SUPERCONDUCTING TRANSITION NEAR A FERROMAGNETIC QUANTUM CRITICAL POINT... 

First order superconducting transition near a ferromagnetic quantum critical point... 

First Order Superconducting Transition near a Ferromagnetic Quantum Critical Point 219... 

The magnetization curve of a two-dimensional ferromagnet near Tc falls off much more abruptly than the one of a three-dimensional ferromagnet Considering the critical behavior of M(T), the temperature is usually replaced by the reduced temperature t = (T — Tc]/Tc, and the critical exponent f of the power law... 

Gai. jMn.jAs. Furthermore, the scaling theory of electronic states near the MIT, discussed in the previous sections, makes it possible to explain the presence of the ferromagnetism on the both sides of the MIT, and a non-critical evolution of 7fc across the critical point (Matsukura et al. 1998b). A comparison between theoretical and experimental data in a wider range of Mn and hole concentrations requires reliable information on the hole density in particular samples, which is not presently available. In appears, however, that in the case of both Gai-jjMnjAs and Im jMnjAs on the insulator side of the MIT, the experimental values of Tc are systematically higher than those expected from the Zener model. 

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