First Measurement of Short-Range-Order Inversion as a Function of Concentration in a Transition Alloy

Diffuse-neutron-scattering and resistivity measurements have been performed on ${\mathrm{Fe}}_{1-c}-{\mathrm{Cr}}_c$ alloys ($c<\mathrm{}0.15\mathrm{}$). A change of sign of the short-range-order parameters near $c=0.1\mathrm{}$ indicates that the alloys exhibit short-range clustering at $c>\mathrm{}0.1\mathrm{}$ and a tendency to form an ordered compound at $c<\mathrm{}0.1\mathrm{}$. Concurrently, the slope of the resistivity versus temperature changes its sign. This inversion of short-range ordering has been predicted by a recent calculation. These experiments are considered to be an important confirmation of the theory.