Influence of atomic ordering on the Fe2Nb antiferromagnetic alloy

Fe2Nb samples were obtained by arc melting, ordered by heat treatment, and finally disordered by means of mechanical alloying with milling times of 0.5, 1, 2 and 4 h. The ordered alloy shows only the hcp-Fe2Nb structure which is paramagnetic at room temperature, and at low temperatures exhibits spin glass and antiferromagnetic behaviours. Mechanical alloying destroys the ordered structure and permits the formation of bcc iron-rich grains. Atomic disorder maintains the antiferromagnetic behaviour of the alloy, but increases its freezing temperature. The Neel temperature of the hcp grains is increased by the apparition of bcc grains. (C) 2013 Elsevier B.V. All rights reserved.