Curie Point and Origin of Weak Ferromagnetism in Hematite

Abstract
The Curie point of α-Fe2 O3 is found by differential thermal analysis (DTA) to be at 725°C, rather than the value of 675°C known from magnetic measurements. Of the theories on the origin of the weak ferromagnetism in this material, only that of Dzialoshinskii can account for all the experimental data. The 675°C is argued to be a point at which the basal plane anisotropy (assumed nonsymmetric) changes sign.