We have studied the magnetic properties of singlehyphen;crystal Dy and Tb in the temperature range from 4.2 to 250 K. We observe the Neacute;el transition for Dy and Tb at 180 and 230 K, respectively. The Curie temperature was found to be 90 and 220 K for Dy and Tb, respectively. These values forTNandTCagree well with earlier measurements by Behrendt (1958) and Koehler (1963). In addition to these transitions, we observe a new anomaly in singlehyphen;crystal Dy near 4.5 K manifested by a reduction of the magnetization in the basal plane with a simultaneous rise in the magnetization along thecaxis. This suggests the magnetic moments may rise out of the basal plane of Dy and form a component along thecaxis at low temperatures. We also observe a small broad peak in the ac susceptibility of Dy near 167 K which is likely due to the vortex state of Dy. The ac susceptibility along thebaxis of singlehyphen;crystal Tb shows a rapid decrease below 30 K while thechyphen;axis susceptibility shows a corresponding increase.
展开▼
