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) identical with 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.