Moment instability in Fe65Ni35 and Fe3Pt invar alloys studied with polarised neutrons

Polarised neutron diffraction measurements on Fe65Ni35 and Fe3Pt invar alloys show that the shape of the magnetisation distribution remains essentially unchanged in the temperature range 100-600 K. This finding is inconsistent with band models of the invar effect. Investigation of the magneto-vibrational scattering shows a strong coupling of the lattice and magnetic degrees of freedom. (C) 2002 Elsevier Science B.V. All rights reserved.