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Discovered by ancient civilizations around 500 BC, magnets have become an essential component in modern technology. Demand for magnets continues to grow as smartphones and other electronic products become ubiquitous. But which metals can engineers use to create a magnetic force? There are four main magnet types:
Diamagnetic
To start, diamagnetic metals are weakly repelled by permanent magnets. Typically made from nickel or iron, permanent magnets retain magnetism after being influenced by an external magnetic field. On the other hand, diamagnetic metals include copper, lead, and graphite. Although they make a weak contribution to magnetic fields — since they barely react with permanent magnets — they are magnetic metals nonetheless. To a certain extent, all materials experience some form of diamagnetism, including trees and clothing.
Superconducting
Next, superconducting metals create a strong repulsion in permanent magnets. These include gallium and tin. All superconductors need to be at an extremely cold temperature (known as the “critical temperature”) for magnetic repulsion to take place. Once the superconductor metal breaches this temperature, it reaches a point where there is zero electrical resistance. Other metals may be conductors, but their impurities prevent them from reaching zero resistance.
Paramagnetic
On the opposite end of polarization, paramagnetic metals are weakly attracted to permanent magnets. Most chemical elements display some degree of paramagnetism, which means they have a positive susceptibility to magnetic fields. However, if there is no external magnetic field influencing them, paramagnets will not have any magnetization. Paramagnetic metals include gold and aluminum.
Ferromagnetic
Finally, ferromagnetic metals have a strong attraction to permanent magnets. When we observe magnetic attraction or repulsion in daily life, we are seeing ferromagnetic materials in action. Only a few metals are ferromagnetic, however, and these include iron, cobalt, nickel, and some rare earth metal alloys. These materials form the basis of many electric products today, such electric motors, hard disks, generators, and much more. Most permanent magnets are ferromagnetic.
