Magnetostructural transition in NdCu2 -: Evidence for an axis conversion like behaviour

The magnetic (H, T)-phase diagram of the orthorhombic compound NdCu2 was investigated for external magnetic fields up to 15 T parallel to the crystallographic c-direction. Magnetization and magnetostriction measurements reveal an anomalous change of the magnetic properties as well as giant magnetostriction (GMS) and large hysteretic effects. This behaviour similar to that observed in some other RCu2 compounds where it has been interpreted as a conversion of the magnetic Ising axis. In contract to these other RCu2 compounds, however, the easy axis of magnetization in NdCu2 is the b-axis. The macroscopic measurements are compared with neutron diffraction experiments which reveal GMS along the b-axis and a new magnetic phase with propagation vector tau = (0.700) in the converted crystal.