What does ferromagnetic mean?
Ferromagnetic describes materials that exhibit the strongest known form of everyday magnetism: they are powerfully drawn to magnetic fields and, crucially, can stay magnetized even after the field is removed. Iron, nickel, and cobalt are the classic examples, along with many of their alloys, and this property explains familiar phenomena from compass needles to refrigerator magnets. The word belongs primarily to the vocabulary of physics and engineering, where it distinguishes true ferromagnets from weakly responsive paramagnetic materials and feebly repelled diamagnetic ones. Its reach is enormous: electric motors, transformers, and data-storage devices all depend on ferromagnetic substances. A notable quirk is that ferromagnetism disappears when a material is heated above its Curie temperature, at which point thermal motion scrambles the alignment of atomic magnetic moments. The adjective derives from ferrum, the Latin word for iron, a fitting tribute to the element whose magnetic behavior gave the phenomenon its name.
adjectiveRelating to or exhibiting ferromagnetism: the property of certain materials, such as iron, nickel, and cobalt, to be strongly attracted to a magnetic field and to retain magnetization after the field is removed.
- Describing a material that exhibits ferromagnetism: strong attraction to magnetic fields and the ability to retain permanent magnetization.
- Relating more generally to ferromagnetism as a physical phenomenon or field of study in solid-state physics.
"Iron is ferromagnetic at room temperature, which is why it sticks to a refrigerator door."
"The hard drive's platters rely on a thin ferromagnetic coating to store data as tiny magnetized regions."
"Above its Curie point, a ferromagnetic substance transitions to a merely paramagnetic state."
Heat a ferromagnetic material past its Curie temperature and its magnetism vanishes — the same iron that clings to your fridge stops being magnetic at around 770°C.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ferromagnetic
The term combines 'ferro-', from the Latin ferrum meaning iron, with 'magnetic', ultimately tracing back through Latin magnes (lodestone) to Greek Magnēs lithos, the stone of Magnesia. It arose in the context of nineteenth-century physics, when scientists distinguished the powerful magnetism of iron from weaker forms of magnetic response. Related descendants of ferrum include ferrous, ferric, and ferroconcrete, while the noun form ferromagnetism names the underlying physical property.
Related word forms
How ferromagnetic is actually used
A technical term used chiefly in physics, chemistry, engineering, and materials science. In everyday speech people usually just say 'magnetic'; 'ferromagnetic' signals a precise scientific context. Strictly speaking, ferromagnetism refers to the specific mechanism of aligned atomic magnetic moments, so scientists reserve the term for materials like iron, nickel, cobalt, and their alloys rather than using it loosely for anything attracted to a magnet.
Easily confused with ferromagnetic
Paramagnetic materials are only weakly attracted to magnetic fields and lose their magnetization immediately when the field is removed, whereas ferromagnetic materials are strongly attracted and can remain magnetized.
Diamagnetic materials are weakly repelled by magnetic fields, the opposite behavior of ferromagnetic materials, which are strongly attracted.