FROM DESIGN TO
PRODUCT

What are rare earth magnets – and what are they used for?

• 2023-02-01

Samarium cobalt (Samarium cobalt 5 or Sm2Co17) and NdFeb (Nd2Fe14B) are both rare earth magnets – the strongest rare earth permanent magnets known.

They are called rare earths because both samarium and neodymium are found in lanthanide metals in the periodic table, and therefore the properties and crystal structure of these magnets are very similar.

Samarium is alloyed with the transition metal cobalt. Neodymium is alloyed with the transition metal iron. So each magnet is a combination of a rare earth metal and a transition metal.

Neodymium magnets also contain very small amounts of boron, which makes them different from samarium cobalt magnets because neodymium iron boron uses three main alloying elements, whereas samarium cobalt uses only two.

Rare earth magnets are the strongest permanent magnets known. They are used in many high-tech applications, such as electric drive motors for cars, smart speakers, smartphones (see our article on NdFeb magnets in smart speakers for smartphones and Internet of Things devices), sensors and more.