Magnetic field
Relation between H and B
Diamagnetic materials produce a magnetization that opposes the magnetic field. Paramagnetic materials produce a magnetization in the same direction as the applied magnetic field. Ferromagnetic materials and the closely related ferrimagnetic materials and antiferromagnetic materials can have a magnetization independent of an applied B-field with a complex relationship between the two fields. Superconductors (and ferromagnetic superconductors) are materials that are characterized by perfect conductivity below a critical temperature and magnetic field. They also are highly magnetic and can be perfect diamagnets below a lower critical magnetic field. Superconductors often have a broad range of temperatures and magnetic fields (the so-named mixed state) under which they exhibit a complex hysteretic dependence of M on B. In the case of paramagnetism and diamagnetism, the magnetization M is often proportional to the applied magnetic field such that:
Magnetic field-90