Magnetic saturation is the state reached when an increase in applied external
magnetic field cannot increase the magnetization of the material further, so the
total magnetic flux density more or less levels off. (Though, magnetization
continues to increase very slowly with the field due to paramagnetism.)
Saturation is a characteristic of ferromagnetic and ferrimagnetic materials,
such as iron, nickel, cobalt and their alloys. Different ferromagnetic materials
have different saturation levels.