Structural changes associated with antiferromagnetic ordering in Mn-rich Mn-Ni alloys

Structural and property changes of face-centered cubic Mn-Ni alloys were investigated in the composition and temperature range of antiferromagnetic ordering. It was found that the onset of domain formation requires a critical (tetragonal) magnetostrictive strain epsilon >or approximately=0.005 to be exceeded. At solute contents c<or approximately=15 at.% Ni this critical strain occurs at the Neel temperature T N ; at c<or approximately=15 at.% Ni this critical strain is attained at some temperature T d <T N . All experimental observations can be interpreted on this basis without invoking the occurrence of a separate structural phase transition cubic-tetragonal.