Magnetism is believed to be caused by the alignment of small, numerous sub-units called poles fields ions domains

Magnetism is believed to be caused by the alignment of small, numerous sub-units called domains. A magnetic domain is a small portion in the magnetic fields of atoms that have grouped together and aligned uniformly. To best describe domains, they are often likened to tiny random magnets pointing at different directions within a material. When the material is magnetized, these tiny magnets align and point towards a unified direction.