Evidence of the c-axis magnetic moment in single-crystal Dy

Abstract

We have studied the magnetic properties of single‐crystal Dy and Tb in the temperature range from 4.2 to 250 K. We observe the Néel 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 for T N and T C agree well with earlier measurements by Behrendt (1958) and Koehler (1963). In addition to these transitions, we observe a new anomaly in single‐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 the c axis. This suggests the magnetic moments may rise out of the basal plane of Dy and form a component along the c axis at low temperatures. We also observe a small broad peak in the acsusceptibility of Dy near 167 K which is likely due to the vortex state of Dy. The acsusceptibility along the b axis of single‐crystal Tb shows a rapid decrease below 30 K while the c‐axis susceptibility shows a corresponding increase.