Shape of temperature dependence of spontaneous magnetization of ferromagnets: Quantitative analysis

Analysis of available experimental data shows that there exists a limited variety of shapes of temperature dependence of spontaneous magnetization. For most metallic ferromagnets the shape (as opposed to scale) of the M-s versus T curve can be characterized by a single dimensionless parameter. A numerical description of the dependence M-s(T) for a particular ferromagnetic material is thus reduced to evaluating three quantities: the saturation magnetization M(0)equivalent to M-s(0), the Curie point T-C, and the shape parameter s. It is demonstrated that classical spin (S=infinity) dynamics fails to describe correctly either of the finite-temperature characteristics, T-C or s.