Contrary to the recent claim that gadolinium behaves as an antiferromagnet with a helical spin structure for temperatures between the spin reorientation (SR) temperature $T_{\mathrm{SR}}$ and the Néel point, the ac susceptibility and low-field bulk magnetization data taken along the [0001] and $\left[101¯0\right]$ hexagonal directions of high-purity gadolinium single crystals over a wide range of temperatures provide ample experimental evidence in favor of the widely accepted view that gadolinium is a normal ferromagnet with a collinear spin structure in the temperature range from $T_{\mathrm{SR}}$ to the Curie point $T_C.$ However, the magnetic behavior of gadolinium is complicated by a rather complex temperature dependence of the easy direction of magnetization for temperatures below $T_{\mathrm{SR}}.$

• Received 17 November 1999

DOI:https://doi.org/10.1103/PhysRevB.62.1114