Magnetostriction and transformation of crystal structure of intermetallic compound NdCo2

Abstract

Ferromagnetic compound NdCo2 has complex magnetic transformation, which are accompanied by changes of the crystal lattice. The purpose of this paper was the investigation of influence of these transformations on the field and temperature dependence of magnetostriction. It was found that near the Curie temperature Tc = 98K, where the transition from cubic to tetragonal phase is observed, there is a maximum in the temperature dependence of the transverse magnetostriction λ⊥(T) in the field B = 4T. In this field λ⊥ reaches high values of λ⊥∼200·10−6 at temperatures higher than Tc. This shows that in this field, the tetragonal distortion and band magnetism of 3d-subsystem remain even at T>Tc. At T<42K λ⊥ decreases in field B = 0.5 T due to phase transition from tetragonal phase to orthorhombic. The curve λ⊥ (H) at T = 10 K anomalies are observed. They are associated with the fact that under the action of the external field there are consistent transitions from orthorhombic phase to tetragonal and then to cubic. Thus, it was found that the compound NdCo2 crystal structure is reconstructed with magnetic field.