What Are Magnets Made Of?

By John Papiewski
What Are Magnets Made Of?

While most materials have some magnetic properties, relatively few can be made into magnets. Iron and a few other related metals can easily become magnetized. When alloyed with other metals or made into compounds, they have stronger magnetism or are easier to make. The rare-earth metal neodymium is the basis of the strongest permanent magnets known. Superconducting metals at cryogenic temperatures also make powerful electromagnets.



Iron

Iron and related elements, such as cobalt and nickel, belong to a family of ferromagnetic metals. They're naturally attracted to magnets and are easily magnetized.

Ceramic

Ceramic magnets are made of strontium carbonate and iron oxide powder, pressed into forms and polished. Though brittle, they have the advantage of low cost and good magnetic strength.

Alnico

Getting its name from aluminum, nickel, and cobalt, alnico is an alloy of these and a few other metals. Until rare-earth magnets were developed in the 1980s, these were the strongest permanent magnets known.

Rare Earths

These magnets are made from alloys of neodymium. They have the greatest strength of any permanent magnet material, opening up new applications. Tiny, powerful speakers, ear buds, toys and motors use rare-earth magnets.

Superconductors

MRIs use powerful superconducting magnets. These are electromagnets cooled in liquid helium, about 4 Kelvins or minus 269 degrees Celsius. The magnets are wound from niobium-titanium or niobium-tin alloy wire, which loses all electrical resistance at these temperatures.

About the Author

Chicago native J.T. Barett has a Bachelor of Science in physics from Northeastern Illinois University and has been writing since 1991. He has contributed to "Foresight Update," a nanotechnology newsletter from the Foresight Institute. He also contributed to the book, "Nanotechnology: Molecular Speculations on Global Abundance."