The Fluctuating Field Ferromagnet at Low Temperatures

Abstract

Neel's concept of fluctuating intermolecular field may be ascribed to localized but migratory elementary magnets in ferromagnetics with non-integral Bohr magneton numbers. This concept allows a low temperature ordering of elementary magnets and a variation with temperature of the effective number of nearest neighbours between which exchange interactions occur. This model alone cannot explain the approach to absolute saturation at 0 °K of a ferromagnetic, but it modifies the constant of the T3/2 law of approach. In the case of ordering by the mutual attraction of parallel elementary magnets, each consisting of a coupled pair of spins (s = 1) the theoretical and experimental values of this constant for nickel are reconciled.