Transport Properties Near Magnetic Critical Points

Abstract

In the last few years intense interest has developed in the nature of second-order phase transitions. Experimental and theoretical investigations have centered primarily on equilibrium properties. Transport or nonequilibrium properties are only now beginning to be intensively studied. Thus far there exists only very limited theoretical work in this area, and little experimental data for comparison. We review the theoretical and the experimental situation (excluding neutron diffraction) as it applies to magnetic systems. Scaling-law theory is summarized and the importance of the dynamic-scaling hypothesis is emphasized. An attempt is made to relate existing experiments to these scaling laws. We conclude that the closest contact between scaling theory and experiment at present comes in the prediction and observation of transitional behavior between the hydrodynamic regime far from the critical point, and the critical regime in which the fluctuation range becomes large compared to other characteristic lengths.