Magnetization and neutron scattering studies of the pressure effect on the magnetic transition in Er_(0.57)Y_(0.43)Co_2

摘要

Neutron powder diffraction was employed to study the pressure effect on the magnetic transition in the pseudobinary Laves-phase compound Er_(0.57)Y_(0.43)Co_2 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 4f (Er) and itinerant 3d (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 (partial deriv)T_c/(partial deriv)p ～ -0.4 K/kbar. The values of the magnetic moments of the Er and the Co ions are found μ_(Er) = 5.40 ± 0.15 μ_B/atom, μ_(Co) = 0.50 ± 0.07 μ_B/atom and 5.35 ± 0.15 μ_B/atom, 0.37 ± 0.09 μ_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.