Magnetic properties and thermal stability of CoFeNi-based amorphous films

CoNiFe-based amorphous films were magnetron-sputtered to investigate their structural and magnetic properties, including annealing-induced effects and interfacial influence from additional layers of Ta and Cu. The amorphous structure was confirmed by diffraction experiments. The magnetic measurements showed a well-defined uniaxial anisotropy in plane, arising possibly from atom oblique incidence effects competing with the stray field of the magnetron. The anisotropy could be influenced by using a Ta buffer layer, though the interfacial reaction gives rise to a dead layer. A coercive force H-c of 1-2 Oe and a magnetization of 680 emu/cm(3) were measured at room temperature; properties which show promise for application in magnetotunneling junction devices. Thermal analyses showed a two-stage crystallization behavior, which started at 400degreesC and ended at about 600degreesC. The Curie temperature of the amorphous phase was estimated to be about 440degreesC. (C) 2004 Kluwer Academic Publishers.