Categories: Guide to Space


[/caption]Magnetism is a fundamental force of the universe, essential to its function and existence in the same way that gravity and weak and strong nuclear forces are. But interestingly enough, there are several different kinds of magnetism. For example, there is ferromagnetism, a property which applies to super magnets, where magnetic properties exist regardless of whether or not there is a magnetic field acting on the material itself. There is also Diamagnetism, which refers to materials that are not affected by a magnetic field, and Paramagnetism, a form of magnetism that occurs only in the presence of an externally applied magnetic field.

Materials that are called ‘paramagnets’ are most often those that exhibit, at least over an appreciable temperature range, magnetic susceptibilities that adhere to the Curie or Curie–Weiss laws. According to these laws, which apply at low-levels of magnetization, the susceptibility of paramagnetic materials is inversely proportional to their temperature. Mathematically, this can be expressed as: M = C(B/T), where M is the resulting magnetization, B is the magnetic field, T is absolute temperature, measured in kelvins, C is a material-specific Curie constant.

Paramagnets were named and extensively researched by British scientist Michael Faraday – the man who gave us Faraday’s Constant, Faraday’s Law, the Faraday Effect, etc. – beginning in 1845. He, and many scientists since, found that certain material exhibited what was commonly referred to as “negative magnetism”. Most elements and some compounds are paramagnetic, with strong paramagnetism being exhibited by compounds containing iron, palladium, platinum, and certain rare-earth elements. In such compounds atoms of these elements have some inner electron shells that are incomplete, causing their unpaired electrons to spin like tops and orbit like satellites. This makes the atoms act like a permanent magnet, tending to align with and hence strengthen an applied magnetic field. However, once the magnetic field is removed, the atoms fall out of alignment and the material return to its original state. Strong paramagnetism also decreases with rising temperature because of the de-alignment produced by the greater random motion of the atomic magnets.

Weak paramagnetism, independent of temperature, is found in many metallic elements in the solid state, such as sodium and the other alkali metals. Other examples include Iron oxide, Uranium, Platinum, Tungsten, Cesium, Aluminum, Lithium, Magnesium, Sodium, and Oxygen gas. Even iron, a highly magnetic material, can become a paramagnet once it is heated above its relatively high Curie-point.

We have written many articles about magnetism for Universe Today. Here’s an article about magnetic field, and here’s an article about what magnets are made of.

If you’d like more info on paramagnetism, check out these articles from Hyperphysics and Physlink.

We’ve also recorded an entire episode of Astronomy Cast all about Magnetism. Listen here, Episode 42: Magnetism Everywhere.


Matt Williams

Matt Williams is a space journalist and science communicator for Universe Today and Interesting Engineering. He's also a science fiction author, podcaster (Stories from Space), and Taekwon-Do instructor who lives on Vancouver Island with his wife and family.

Recent Posts

Astronomers are Searching for a Galaxy-Wide Transmitter Beacon at the Center of the Milky Way

Researchers with the SETI Institute have monitored the center of the Milky Way for possible…

11 hours ago

Betelgeuse is Almost 50% Brighter Than Normal. What’s Going On?

Whenever something happens with Betelgeuse, speculations about it exploding as a supernova proliferate. It would…

18 hours ago

Three New Astronauts Arrive at the Chinese Space Station, Including the Country's First Civilian

China's Shenzou-16 mission just delivered three taikonauts to the Tiangong space station, performing the most…

18 hours ago

These New Computer Simulations of the Sun are Hypnotic

It's almost impossible to over-emphasize the primal, raging, natural power of a star. Our Sun…

2 days ago

JWST Scans an Ultra-Hot Jupiter’s Atmosphere

When astronomers discovered WASP-18b in 2009, they uncovered one of the most unusual planets ever…

2 days ago

You Can Detect Tsunamis as They Push the Atmosphere Around

Anyone who's ever lived along a coastline or been at sea knows the effects of…

2 days ago