Introduction to Superconductivity/Magnetism

Types of Magnetic materials

Diamagnetism

There are a lot of quantum mechanics involved with diamagnetism, but in a basic sense,  diamagnetic objects typically repel when exposed to magnetic fields. Diamagnetic elements include hydrogen, beryllium, poor metals, most nonmetals and semimetals, halogens, and noble gases.

Paramagnetism

The opposite of diamagnetism, paramagnetic substances attract magnetic forces when exposed to them. Paramagnets are only magnetic when in the presence of an established magnetic field and do not give off their own magnetic fields, making them different from ferromagnets. The alkali metals, alkaline earth metals, most transition metals, lanthanide metals (including neodymium) oxygen, aluminum, and tin are all paramagnetic.

Ferromagnetism

Ferromagnets are permanently magnetic. They are objects with strong magnetic attraction, regardless of whether or not they are in the presence of a magnetic field. The term comes from “ferrum”, the Latin word for iron (a ferromagnetic element). Ferromagnets include iron, nickel, and cobalt.

Antiferromagnetism

The name might be a mouthful, but the theory is relatively simple. Antiferromagnets are just that — the opposite of ferromagnets. They repel other metals without the presence of a magnetic field. However, it should be noted that this typically only occurs at very low temperatures and most antiferromagnets are simply paramagnets at room temperature. The only known antiferromagnetic element is chromium.

Ferrimagnetism

Note the vowel difference. Ferrimagnets, like ferromagnets are magnetic even without an active field. Ferrimagnets contain electrons that both attract like ferromagnets and repel like antiferromagnets. However, there are more electrons that attract than repel, leading to ferrimagnets’ own classification.

Superparamagnetism

Like paramagnets, superparamagnets are attracted to magnetic fields when exposed to them. As the prefix “super” suggests, these magnets are much more attracted than other paramagnets.