Magnetic Behavior in the Transition Region of a Hematite Single Crystal

Abstract

The magnetic behavior in the transition region of a hematite single crystal from Elba has been investigated carefully. The remanence-temperature relationship and the thermal hysteresis effect (i.e., the remanence is a double-valued function of temperature) have been obtained for each of three mutually perpendicular directions of the crystal in the temperature range between 488° and 77°K. A graphical representation of the ferromagnetic state has been constructed to show the direction, the magnitude, and the turning of the remanent magnetization vector with the temperature in the transition region. Another experiment, which consists of measuring the remanence along different directions in the plane containing the [111] direction, and the projection of the remanent magnetization vector in the (111) plane for three different temperatures, also has been carried out. These experimental data show that the direction and the magnitude of the remanent magnetization vector changes continuously between the [111] direction and the (111) plane when the temperature changes through the transition region.