Effect of manganese on antiferromagnetic transition in Mn-Fe-(Cu) alloys

There are two antiferromagnetic states found in the Mn-Fe alloys according to composition. These are: low-manganese state I and a high-manganese state II. TN of the alloys increased from 198 °C to 222 °C with increasing in manganese content from 45.9% to 61.4% in the antiferromagnetic state I and keeps almost unchanged on 154 °C when manganese content further increased to 71.3%, 81%, and 86% in the antiferromagnetic state II. In state I, the temperature gradient of the resistance below the Neel temperature is smaller than the one above the Neel temperature. This tendency is opposite to that of specimens in state II.