Magnetic analysis of a melt-spun Fe-dilute Cu60Au35Fe5 alloy

Abstract

The magnetic properties of a melt-spun Cu60Au35Fe5 alloy are examined by X-ray diffraction (XRD), magnetic measurements, and transmission electron microscopy (TEM). The XRD pattern of an as-spun sample indicates the formation of a solid solution of Cu and Au with no Fe phase, whereas that of the annealed sample (773K×36ks) shows a small amount of the α-Fe phase because the Fe atoms precipitate during annealing. TEM observations and EDX analysis of the as-spun sample show no distinct Fe-rich domains, implying that some Fe atoms are dissolved in the matrix, and others form very fine magnetic clusters. Moreover, magnetic measurements indicate the presence of magnetic clusters and isolated Fe atoms. The AC magnetic susceptibilities show that the as-spun sample has a sharp cusp around 20K, which is characteristic of spin glass behavior. The simulations of the M–H curves of the as-spun sample measured at 77 and 300K, show that most Fe atoms are dissolved in the matrix as isolated atoms, not as clusters. Additionally, the calculated rate of clustering in the as-spun sample tends to decrease with temperature, suggesting that the magnetic exchange interactions are weak.