Antiferromagnetism of γ Iron Manganes Alloys

Abstract

The magnetic phase diagram of γ Fe-Mn alloys has been investigated in the whole range of composition by neutron diffraction and other techniques. The f.c.c. phase of Fe-Mn alloys with less than 40 at. % iron and more than 85 at. % iron was stabilized by addition of small amounts of copper and carbon respectively in the alloys. An antiferromagnetic long range order was detected in the whole range composition. The antiferromagnetism of this alloy system Fe x -Mn 1- x was found to be classified into three distinct groups according to the composition. They are 1) 0≤ x ≤0.3, 2) 0.4≤ x ≤0.8, and 3) 0.8≤ x ≤1. The magnetic phase of the second group is markedly different from other two groups. The results agree qualitatively with the prediction based on the band theory.