Magnetic AC susceptibility study of the cobalt segregation process in melt-spun

2019-06-07 08:48:04

AC magnetic susceptibility dependent

责任者: Lopez, A.;Lazaro, F.J.;von Helmolt, R.;Garcia-Palacios, J.L.;Wecker, J.;Cerva, H. 单位: Universidad de Zaragoza, Zaragoza, Spain 来源出处: Journal of Magnetism and Magnetic Materials,1998,187(2):221-230 摘要: Temperature and frequency-dependent AC susceptibility has been used to characterize Cu90Co10 melt-spun ribbons, about 15 µm thick, in order to see to what extent this technique yields information about the segregation of cobalt in this alloy. The interpretation of the results includes, as a prerequisite, a transmission electron microscopy (TEM) characterization and makes use of previous field-dependent magnetization data on the same samples. Due to their different dynamical magnetic properties, the large intergrain precipitates, the small intragrain aggregates and the remaining Cu-Co solid solution, previously detected in these alloys, are independently observed by AC susceptibility as ferromagnetic, superparamagnetic and spin-glass species. Contrary to other, mostly local, microstructural characterization techniques of use with nanostructured materials, the AC susceptibility yields information about the whole sample. Furthermore, unlike the measurement of the temperature-dependent magnetization which is the magnetic technique mostly used until now, the results are basically independent of the thermal history. The correlation between microstructure and magnetic properties is illustrated by a scheme which includes magnetization, AC susceptibility and TEM data. 关键词: Magnetic materials;Copper alloys;Melt spinning;Magnetic permeability;Thermal effects;Segregation (metallography);Paramagnetism;Magnetization;Solid solutions;Ferromagnetism;Metallographic microstructure;Magnetic field effects;Transmission electron microscopy;Superparamagnetism