Analytical behavior of short-range order scattering of Cu-rich Cu-Mn near theΓpoint

Abstract

Small-angle neutron scattering with scattering vectors in the range of 0.01 to 0.17 reciprocal lattice units was measured for a single crystal of Cu-17.2 at.% Mn aged at 483 K. At large scattering vectors, a directional dependence of the scattering intensity is observed, with slightly higher values along 100 than along 110. The difference in intensities continuously decreases with decreasing scattering vector. The present data contradict the results of a previous synchrotron radiation study where it was concluded that short-range order scattering is nonanalytical at the point. The discrepancy is traced back to multiple Bragg scattering with high-energy x rays.

Static atomic displacements inCu̱-Mnmeasured with diffuse x-ray scattering

“…4 While this behavior was deduced from high-energy x-ray measurements, a subsequent experimental investigation by smallangle neutron scattering was unable to show the expected features. 5 ͑ii͒ In a comprehensive study of Gödecke ͑see Ref. 6 and references therein͒, anomalies in the temperature dependence of macroscopic properties ͑dilatation, elastic modulus, and electric resistivity͒ were noted and interpreted as transitions between different phases ͑Cu 5 Mn and Cu 3 Mn͒.…”