Mössbauer Effect in Nickel‐Rich Nickel‐Manganese Alloys

Nickel‐rich nickel‐manganese alloys with manganese concentrations of 2, 4, and 16 at% have been investigated at various temperatures by Mössbauer spectroscopy using Fe 57 as the probe nucleus. The sample with 16 at% Mn concentration has been studied in detail for various heat treatments. For all heat treatments it shows anomalous spectra consisting of an intense central line together with a magnetic structure, over a wide range of temperatures. Three different possibilities have been considered to account for the anomalous spectra. They are the co‐existence of two phases corresponding to long‐range order and short‐range order, the co‐existence of nickel‐rich and manganese‐rich regions, and relaxation effects.