Ferromagnetism is a form of magnetism that can be acquired in an external magnetic field and is usually retained in its absence. Thus, ferromagnetic materials like iron and nickel are used to make permanent magnets. This type of magnetism is caused by spinning electrons in the atoms of the material, which act as tiny weak magnets. They align parallel to each other within small regions of the material to form areas of stronger magnetism. What other substances exhibit ferromagnetism? Discuss