How Strong Are Rare Earth Magnets?

How Strong Are Rare Earth Magnets?
Magnets are an integral part of many technologies and appliances in the 21st century.

From tiny fridge magnets that hold to-do lists to powerful ones that create magnetic fields for electricity generation from wind turbines, there are many different types of magnets.

The world’s strongest magnets, also known as rare earth magnets, are made by alloying certain rare earth elements with other materials.

But just how strong are rare earth magnets, and what makes them so powerful?

Measuring Magnet Strength
The above infographic uses data from First4Magnets to compare the strength of magnets. But before looking at the strongest magnets, it’s essential to understand how to measure magnetic strength.

The maximum energy product, measured in mega-gauss-oersteds (MGOe), is one of the primary indicators of magnetic strength. It is a multiplication of two measurements: a magnet’s remanence and its coercivity.

To become magnets, ferromagnetic substances need to enter the magnetic field of an existing magnet. Remanence, measured in Gauss, is the magnetism left in the magnet after removing the external magnetic field.
Coercivity is the energy required to bring a magnetic material’s magnetism down to zero. Measured in oersteds, it essentially captures the magnetic material’s resistance to demagnetization.
The Strength of Rare Earth Magnets
Each magnet has a grade, which typically denotes its strength. For example, a neodymium magnet of grade N42 has a strength of 42MGOe.

To put the power of two common rare earth magnet grades into perspective, here’s how their strength compares with common grades of other permanent magnets:

Read more: How Strong Are Rare Earth Magnets?