Materials that strong magnets can attract are classified as ferromagnetic, paramagnetic, or diamagnetic. These classifications are used to describe the degree to which a material can be attracted to a magnet.
1. Ferromagnetic materials
Ferromagnetic Materials: Gadolinium, Iron, Cobalt, and Nickel
Ferromagnetic materials (containing the elements iron, nickel, cobalt, or gadolinium) are attracted magnetically.
Ferromagnetic materials are so classified because their atoms possess a high level of magnetism due to the way their electrons are arranged. Electrons are easily aligned in the same magnetic direction, making them attractive to magnets.
Most stainless steel varieties are classified as ferromagnetic, but not all are ferromagnetic, for example, austenitic stainless steel is a type of non-magnetic stainless steel.
Whether stainless steel is classified as ferromagnetic depends on the alloy it is made of, as some alloys contain high nickel, which can negatively affect magnetism.
2. Paramagnetic materials
Because paramagnetic metals have a limited number of electrons aligned in the same magnetic direction, their attraction to magnets is very weak. However, these metals are not strong enough to generate their own magnetism.
In contrast, they are about a million times weaker than ferromagnetic materials, which means their magnetic fields can only be measured with very sensitive instruments, such as magnetometers.
Examples of paramagnetic materials are aluminum, uranium and platinum.
3. Antimagnetic materials
Diamagnetic materials are metals that weakly repel magnets when placed near strong magnetic fields. They themselves create small magnetic fields with opposite poles, making the two magnetic fields repel each other.
Metals such as bismuth and carbon graphite are types of diamagnetic materials.
4. Non-magnetic materials
Nonmagnetic materials are those that have atoms that cannot become magnetic, no matter how much magnetic field they are exposed to. For example, wood, plastic and glass are non-magnetic substances.