Low-temperature magnetic properties of dysprosium single crystals

The magnetic properties of three single crystals of dysprosium have been investigated along the principal directions of the hexagonal close-packed structure, over the temperature range 4 to 300 °K and in applied fields up to 18 kOe. The measurements along the a and b directions agree in general with the previous work. Along the c direction a small spontaneous moment is observed, appearing at (125 ± 2) °K, (89 ± 3) °K and (88 ± 4) °K for the three crystals studied. The corresponding values of the spontaneous moment at 0 °K are (1.9 ± 0.4) e.m.u. g -1 , (2.7 ± 0 3) e.m.u. g -1 and 2.6 ± 0.3 e.m.u. g -1 . An analysis of the results indicates that the transition from antiferromagnetism to ferromagnetism is controlled by the strong dependence of the indirect exchange interaction with lattice dimensions.