Editing Curie temperature (section)

=== Paramagnetic ===
{{main|Paramagnetism}}

A material is paramagnetic only above its Curie temperature. Paramagnetic materials are non-magnetic when a [[magnetic field]] is absent and magnetic when a magnetic field is applied. When a magnetic field is absent, the material has disordered magnetic moments; that is, the magnetic moments are asymmetrical and not aligned. When a magnetic field is present, the magnetic moments are temporarily realigned parallel to the applied field;<ref name=Dekker1>{{harvnb|Dekker|1958|pp=217–20}}</ref><ref name=Levy4>{{harvnb|Levy|1968|pp=}}</ref> the magnetic moments are symmetrical and aligned.<ref name=Fan>{{harvnb|Fan|1987|pp=164–65}}</ref> The magnetic moments being aligned in the same direction are what causes an induced magnetic field.<ref name=Fan/><ref name=Dekker>{{harvnb|Dekker|1958|pp=454–55}}</ref>

For paramagnetism, this response to an applied magnetic field is positive and is known as [[magnetic susceptibility]].<ref name=Ibach>{{harvnb|Ibach|Lüth|2009}}</ref> The magnetic susceptibility only applies above the Curie temperature for disordered states.<ref name=Mendelssohn3>{{harvnb|Mendelssohn|1977|p=162}}</ref>

Sources of paramagnetism (materials which have Curie temperatures) include:<ref name=Levy1>{{harvnb|Levy|1968|pp=198–202}}</ref>
* All atoms that have unpaired electrons;
* Atoms that have inner shells that are incomplete in electrons;
* [[Radical (chemistry)|Free radicals]];
* Metals.

Above the Curie temperature, the atoms are excited, and the spin orientations become randomized<ref name=Levy/> but can be realigned by an applied field, i.e., the material becomes paramagnetic. Below the Curie temperature, the intrinsic structure has undergone a [[phase transition]],<ref name=Cusack>{{harvnb|Cusack|1958|p=269}}</ref> the atoms are ordered, and the material is ferromagnetic.<ref name=Fan/> The paramagnetic materials' induced magnetic fields are very weak compared with ferromagnetic materials' magnetic fields.<ref name=Cusack/>