Temperature dependence of the giant magnetostriction of submicrocrystalline dysprosium

The temperature dependence of the magnetostriction of Dy was measured in various structural states. A submicrocrystalline state was created by intense plastic deformation on Bridgman anvils. Intermediate-and large-grain states were obtained by annealing samples in a vacuum at 573 and 873 K respectively. In the large-grain state, plots of the magnetostriction versus temperature exhibit a kink at around 85 K, which is evidence of a magnetic phase transition from ferromagnetism to helical antiferromagnetism. In the submicrocrystalline state these curves have no kinks and decrease smoothly to zero at high temperatures. This is interpreted as the absence of helical antiferromagnetic order in the sample.