The remanent magnetization of haematite single crystals

Abstract

The variation of the remanent magnetization with temperature of several synthetic and natural single crystals of haematite has been measured in the temperature range 60 to –90 °C. Particular attention was given to the measurement of the remanence at temperatures close to the transition temperature. The remanent magnetization of the synthetic crystals showed a sharp reduction over a narrow temperature range; the natural crystals showed a much smaller reduction over a wider temperature range. All the specimens were found to be magnetic at low temperatures which is not in accord with theoretical predictions. The effect of annealing at high temperatures on the behaviour of the remanent magnetization was investigated. The results of measurements of the remanent magnetization of specimens which had been subjected to fast neutron irradiation are also reported.