On the anomalous temperature-dependent magnetostriction in intermetallic DyFe2

The anomalous temperature dependence of the magnetostriction in single-crystal DyFe2 has been an unsolved problem in magnetism for some 27 years. In this paper, it is shown that an explanation can be provided, within the constraints of the Callen and Callen model, provided changes in the second-, fourth-and sixth-order crystal field energies of the rare earth ion are all taken into account. In particular, it is shown that the peculiar temperature dependence of the magnetostriction in DyFe2 is due to competition between n = 2, 4 and 6 crystal field distortions, whose temperature dependence can be accurately modelled using the Callen and Callen model.