Structural and magnetic investigations on metastable Ag–Fe nanophase alloy

Nanocrystalline Ag–Fe alloy samples of various compositions were synthesized by chemical reduction method using sodium borohydride as the reducing agent. The structure analysis of the as prepared and the annealed samples were carried out. The fcc structure of the as prepared samples was stable up to 400 °C. As bulk Ag and Fe are immiscible metals, nanophase alloy formation of these two metals was studied from the broad exothermic peak observed and the enthalpy changes were calculated from the differential scanning calorimetric analysis. The presence of Ag and Fe in their metallic form was verified by performing X-ray photoelectron microscopy studies. The microstructure of these samples reveals that the particles are nanosized. The results of the magnetic characterization of the as synthesized and annealed Ag50Fe50 sample and the conclusions drawn there from are in correlation with the metastable nature of the samples up to 400 °C and the phase changes in the sample annealed at 500 °C.

► Alloy of immiscible Ag and Fe is synthesized by single step chemical method at ambient conditions.
► Temperature dependent structure and magnetic behavior of the samples are analyzed.
► Samples with desired composition and magnetic properties can be tailored by this method.