Saturation
Seen in some magnetic materials, saturation is the state reached when an increase in applied external magnetic field H cannot increase themagnetization of the material further, so the total magnetic flux density Bmore or less levels off. (It continues to increase very slowly due to thevacuum permeability.) It is a characteristic particularly of ferromagnetic (andferrimagnetic) materials, such as iron, nickel, cobalt and their alloys.