The theoretical intrinsic saturation flux density for iron, nickel, and cobalt can be calculated using Eq. (1.345) as follows. Typically, the intrinsic saturation flux density Bi is measured and the number of Bohr magnetons per atom n0 is calculated.
The ferromagnetic properties of materials disappear when the temperature becomes high enough. This temperature is called the Curie temperature Tc or the Curie point. Iron (Tc = 770°C), nickel (Tc = 358°C), and cobalt (Tc = 1130°C) are the only ferromagnetic materials that have Curie points above room temperature. Some rare earth metals like gadolinium (Tc = 16°C), dysprosium (Tc = -168°C), and holmium are ferromagnetic, but their Curie points are below room temperature.
