Ferromagnetic substances are materials that exhibit strong magnetism due to the alignment of their atomic magnetic moments in the same direction, even without an external magnetic field. This property allows them to become permanently magnetized and strongly attracted to magnets. Common ferromagnetic materials include pure forms, alloys, or compounds of iron, cobalt, nickel, and certain rare-earth metals

. These materials contain regions called magnetic domains, where billions of atoms have their magnetic moments aligned parallel. In an unmagnetized state, these domains are randomly oriented, canceling out the overall magnetism. When exposed to an external magnetic field, the domains align in the field's direction, magnetizing the material. If all domains align, the material reaches magnetic saturation and exhibits strong permanent magnetism

. Ferromagnetic materials are essential in many industrial and technological applications, such as electromagnets, electric motors, generators, transformers, and magnetic storage devices

. They also show properties like high magnetic susceptibility, large positive magnetization, and the ability to retain magnetization (hysteresis)

. In summary, ferromagnetic substances are materials that can be strongly magnetized due to the parallel alignment of atomic magnetic moments within domains, with iron, cobalt, and nickel being the primary examples