Magnetization and neutron scattering studies of the pressure effect on the magnetic transition in Er Y Co

Neutron powder diffraction was employed to study the pressure effect on the magnetic transition in the pseudobinary Laves-phase compound Er_0.57Y_0.43Co₂ and to determine the magnetic moments of the Er- and Co-subsystems. Our studies reveal that the onset of long-range magnetic order for both the localized 4 f (Er) and itinerant 3 d (Co) electron moments appears at about the same temperature at ambient pressure. The pressure effect on T_c is found to be negative and equal for both sublattices, namely T _c / p ∼ - 0.4 K/kbar. The values of the magnetic moments of the Er and the Co ions are found = 5.40±0.15μ _B /atom, = 0.50±0.07μ _B /atom and 5.35±0.15μ _B /atom, 0.37±0.09μ _B /atom, for p = 0 and 6 kbar, respectively. Our experimental results give evidence for short-range magnetic order formation at temperatures already above T_c and for a coexistence short- and long-range order below T_c down to 4 K. Received 20 December 2001 / Received in final form 12 June 2002 Published online 31 October 2002 RID="a" ID="a"e-mail: andrew.podlesnyak@psi.ch