Neutron-scattering and Monte Carlo study of short-range order and atomic interaction inNi0.89Cr0.11

The homogeneous short-range-order (SRO) equilibrium state of a quenched ${\mathrm{Ni}}_{0.89}$ ${\mathrm{Cr}}_{0.11}$ alloy was studied by diffuse neutron scattering. Intensity maxima due to short-range order were found at 1(1/20 reciprocal lattice points. Values for the atomic interaction energies are calculated for 30 neighboring shells from the SRO parameters by use of the inverse Monte Carlo method and compared to the results based on a mean-field approximation (Krivoglaz-Clapp-Moss). By a direct Monte Carlo calculation the Ising model with long-range pair interactions has proved to be consistent with the observed short-range order. The pair-interaction energies indicate the existence of a defined Fermi surface in a 〈110〉 direction even for this disordered alloy with a high residual resistivity. Based on further Monte Carlo calculations we conclude that the pair interactions depend on composition.