MAGNETOSTRICTION OF THE NDCO5 UNIAXIAL PERMANENT-MAGNET

Magnetostriction measurements, between approx. 5 and 300 K, of powder magnetically aligned samples of the hexagonal compound NdCo//5, in strong pulsed magnetic fields up to 15 T are reported. The measurements have been performed parallel, perpendicular and at 45 degree to the alignment c-axis, for the field also applied in those directions. This set of measurements allows us to determine the six irreducible magnetoelastic modes related to the strain dependence of the isotropic exchange, and to the strain dependence of the crystalline field anisotropy energy. Anomalies on the strains, associated with the spin reorientation (SR) regime are observed. The irreducible magnetoelastic coupling constants at 0 K have been estimated, although the point charge model is far from agreement with those results.