Magnetic properties of amorphous Fe<inf>40</inf>Ni<inf>38</inf>B<inf>18</inf>Mo<inf>4</inf>ribbons containing nanocrystallites

Abstract

Cut Fe40Ni38B18Mo4ribbons were annealed for two hours at various temperatures Tabetween 400 and 540°C. All the ribbons were subjected to XRD, VSM (vibrating sample magnetometer) and ME (Mossbauer effect spectroscopy) investigations. A differential thermal analysis scan of an as-cast ribbon showed the presence of two exothermic peaks, the first beginning at 419.9°C and peaking at 429.7°C and the second beginning at 497.3°C and ending at 546.2°C. The XRD patterns of the ribbons showed the formation of FeNi3nanocrystallites in the lower T′aribbons and (Fe, Ni, Mo)23B6crystallites in the ribbons annealed above 470°C. Different behaviors of the saturation magnetization were seen in the ribbons annealed between 400 and 450°C, between 450 and 490°C, and between 490 and 540°C. The ME spectra of the ribbons annealed in the three different temperature ranges also pointed to the presence of three crystalline Fe-compounds in these ranges. The XRD patterns and the coercivities (Hc) of the lower Taribbons point to the formation of nanocrystallites in these ribbons. © World Scientific Publishing Company.