A superconducting magnet is a type of electromagnet built from coils of superconducting wire. When cooled to cryogenic temperatures, these wires conduct electricity with zero resistance, allowing the magnet to generate extremely strong, stable magnetic fields without losing energy as heat. In fact, superconducting magnets can generate fields over 2,000 times stronger than the magnets on your refrigerator! 

Superconducting magnets are used in applications that require intensely strong and stable magnetic fields—far beyond what traditional magnets can generate—like MRI machines, particle accelerators, maglev trains, and fusion reactors.

The History of Superconducting Magnets

Superconductivity itself was discovered in 1911 by Dutch physicist Heike Kamerlingh Onnes, who noticed that mercury, when cooled to extremely low temperatures (below 4.2 Kelvin), suddenly lost all electrical resistance.

The first practical superconducting magnet was built in 1961 by researchers at MIT, using niobium-tin (Nb₃Sn) wire. This breakthrough enabled magnets with significantly higher field strengths and zero electrical resistance in their coils, making them more efficient and powerful than conventional electromagnets.

These magnets are opening new frontiers in nuclear magnetic resonance, electron magnetic resonance, quantum physics, and even the pursuit of clean fusion energy. This breakthrough technology—especially when combining low-temperature superconductors (LTS) with high-temperature superconductors (HTS)—makes it possible to achieve field strengths beyond 25 Tesla (T). 

In 2021, MIT developed a record-breaking 20 T HTS magnet, a breakthrough considered essential for making compact fusion power plants possible. You can read more about that on our blog.

What Makes Superconducting Magnets So Powerful?

The key lies in materials called superconductors, which can carry electrical current without resistance when cooled to extremely low temperatures. By combining LTS with HTS materials, scientists can construct magnets that exceed the 21 T limit of traditional LTS-only designs.

To put this into perspective:

  • Your fridge magnet measures about 5 millitesla (mT).

  • A medical MRI magnet operates around 1.5–3 T.

  • The world’s most advanced superconducting magnets can surpass 25 T.

Researchers from MIT and the National High Magnetic Field Laboratory emphasize that superconducting magnets are crucial to the future of fusion energy because they enable compact and efficient plasma confinement.

How Do Superconducting Magnets Work?

A superconducting magnet typically has two main parts:

  • Outsert: Made from LTS materials like niobium-tin (Nb3Sn) and niobium-titanium (NbTi).

  • Insert: Uses HTS materials that can handle higher magnetic fields.

Because LTS-only designs top out around 21 T, the dual-component system is essential. Both sections are immersed in liquid helium at 4.2 Kelvin (-452°F) to stay superconductive. Any increase in temperature can cause a quench, when the coils lose superconductivity and the magnet rapidly releases stored energy.

Explore More

Curious about how magnets impact both science and nature? Learn more about magnetoreception in animals and discover how creatures like sea turtles and birds rely on magnetic fields to survive.

At Apex Magnets, whether you’re a researcher, engineer, or educator, we’re here to provide expert guidance, fast shipping, and custom solutions to help you succeed.

While superconducting magnets represent the extreme edge of magnetism, most industries and consumers need practical, durable solutions. At Apex Magnets, we stock a wide variety of neodymium magnets for applications in retail displays, manufacturing, scientific testing, and everyday organization. 

If you need further assistance or have questions, please don't hesitate to contact us. 

 

Magnets can be dangerous. Neodymium magnets, especially, must be handled with care to avoid personal injury and damage to the magnets. Fingers and other body parts can get severely pinched between two attracting magnets. Bones can be broken by larger magnets. 

Visit our Magnet Safety page to learn more.