Structural and magnetic properties of Cu80Fe5Ni15 granular ribbons

Abstract Microstructure and magnetic properties of as-quenched melt-spun Cu 80 Fe 5 Ni 15 ribbon have been studied. The microstructure was investigated with X-ray diffraction and transmission electron microscopy (TEM). Magnetization measurements, Mossbauer spectrometry has been used in order to determine the magnetic properties. The microstructure of the ribbon is compatible with the presence of two spinodally decomposed FCC phases: a Cu-rich and a (Fe,Ni)-rich phase. The Mossbauer spectrum was well adjusted with two contributions: one from the Cu-rich phase and the other from the (Fe,Ni)-rich phase. From Mossbauer and ZFC/FC measurements, the ribbon shows a superparamagnetic behavior at 300 K, and a Super Spin Glass behavior below T g =20 K. Fitting the magnetization curves provided a medium size of the magnetic particles diameter of 3.1 nm, with the maximum magnetic particle diameter calculated from ZFC/FC curve of 11 nm. Finally, magnetoresistance curves show no hysteresis, and the values measured were 15% at 5 K and 0.2% at 300 K for a maximum applied field of 50 kOe.