Invar alloys Ni 31 (Fe 69-x Cr x ) x=3, 4, 6 and 8 (at.%) in the temperature range 120-400 K have been studied by magnetic Messbauer methods. It is find out absence of a hyperfine structure 57 Fe nuclei magnetically ordered for with x=6 8. The can be represented as system superparamagnetic clusters, moments which relax between differently populated energy levels. phenomenon explained increased ...
