When iron is heated, it loses its strong magnetic properties. However, as the metal cools, it would become magnetic. Nickel at 356 degrees Centigrade and Cobalt at 1075 degrees Centigrade. At low temperatures, certain other metals are ferromagnetic. Dysprosium becomes ferromagnetic at -188 degrees Centigrade.
Magnetism is a property of the atom itself.
In most materials the atomic magnets are randomly oriented, so that most of the effect is cancelled out. Vacuum has a permeability of 1.00. Paramagnetic substances range between 1.00 and 1.01. Nickel has a permeability of 40, cobalt of 55, while iron is in the thousands. This reinforcement produces strong fields within the domains.