Magnetic properties of MnBi prepared by rapid solidification

Abstract

The magnetic properties of the low-temperature phase of MnBi, prepared by rapid solidification, have been measured in a pulsed field over the temperature range 80--625 K. The anisotropy field, obtained by the singular-point-detection technique, is found to increase with temperature and has a maximum value of 9 T at 530 K. A fit to the saturation-magnetization measurement gives a virtual Curie point of 775 K. The coercive field is fitted by a hybrid domain-wall-pinning theory which yields, at 300 K, a domain-wall energy of 15.6 erg/${\mathrm{cm}}^{2}$ and a wall thickness of 70 \AA{}. Below 200 K, the presence of a ferrimagnetic phase is detected. Its critical field associated with spin reversal is a convex function of temperature having a maximum value of 8 T at 120 K.