Magnetic Properties of Metastable bcc and fcc Fe–Cu Alloys Produced by Vapor Quenching

Abstract

High concentration Fe_1−xCu_x alloys have been obtained by rf sputtering technique and investigated by X-ray diffraction and magnetization measurements. The bcc phase is extended over the region with x=0–0.4, while the fcc phase with x=0.6–1.0. For x=0.4–0.6, we have the mixed phase of bcc and fcc. The lattice constant of bcc phase increases slightly and that of fcc phase decreases with increasing x. In the bcc alloys, the average magnetic moment decreases with increasing x and deviates upwards from the simple dilution law. In the fcc alloys, the magnetic moment also decreases with increasing x but it deviates downwards from the simple dilution law. The Curie temperature, T_c, of the Fe_1−xCu_x alloys decreases abruptly with increasing x: T_c is higher than 750 K for the bcc alloys, while it is lower than 320 K for the fcc alloys and become 0 K at about x=0.92.