Observations on the magnetic transition in hematite at -15°C

Abstract

Abstract An examination is made of the magnetic behaviour of hematite, αFe2O3, in the region of the antiferromagnetic transition temperature (−16°c). In this examination it is shown that the magnetic properties of hematite may be ascribed to two magnetically independent components of ferromagnetism, one dependent upon the antiferromagnetic transition whilst the other is independent of this transition. The magnetic properties of these two components have been determined firstly from a series of measurements with an astatic magnetometer, and then, by direct measurement at low temperature (−75°c), the magnetic properties of one component have been measured directly. These observations are critically discussed with reference to the magnetic structure for hematite proposed by Néel, and the inadequacy of this magnetic structure in accounting for some of the observations is pointed out.