Curie Temperature

Synonyms

Curie point

The critical temperature above which any material loses its permanent magnetism.

A rock containing magnetic minerals loses its permanent magnetism when heated up to reach a critical temperature. This is the Curie temperature or Curie point, ϑ _c , above which the rock is paramagnetic. On the atomic level, below ϑ _c , the magnetic moments are aligned in their respective domains and even a weak external field results in a net magnetization. As the temperature increases to ϑ _c and above, however, fluctuations due to the increase in thermal energy destroy that alignment.

Strongly magnetic minerals are all of ferrimagnetic type, in which neighboring magnetic moments are aligned antiparallel, as in antiferromagnetism, but unequal numbers or strengths give a net magnetization. Among them, magnetite, one of the members of the titanomagnetite solid-solution series, is the most important magnetic mineral to geophysical studies of crustal rocks (Stacey, 1992). There are many...