Changes of easy axis during the magnetization of dysprosium

Abstract

Changes in the easy axis of magnetization of dysprosium, within the basal plane, between 77 and 160 K and in applied fields up to 1.25 T, reported by Bly et al. [1] have been reinvestigated and some inconsistencies have been resolved. Changes were only confirmed above 132 K, where the b axis is easy just above the critical field. On increasing the applied field the basal plane anisotropy dies away reappearing with the a axis easy. The changeover occurs at field and temperature values very close to those where a magnetoresistance anomaly has been observed by Akhavan et al. [2]. It is shown that this change may be explained in principle, without any change in the crystal field, by the narrowing of a fan-like spin structure occurring as an intermediate phase between the helical anti-ferromagnetic and the ferromagnetic phases. Between 77 and 110 K anomalies in torque curves in low fields are attributed to domain processes.