Microscopic origins of diamagnetic, ferromagnetic and paramagnetic magnetization

A magnetic field produces induced magnetic dipoles in all types of atom, and it also changes the orientation of any permanent magnetic dipoles that are associated with atoms or molecules. Alignment of these magnetic dipoles creates a macroscopic magnetization of the material, analogous to the polarization produced by an electric field. Macroscopic objects contain many atoms or molecules. The electrons circulating these atoms or molecules act like tiny current loops producing a magnetic field. Also the spin of the electrons makes a contribution. So each atom makes two contributions. Some atoms have no permanent magnetic moment because the resultant moment is zero. However, there are many types of atom where the cancellation is incomplete, and these have a permanent magnetic moment.