Amorphous Whiskers of a Cobalt–Gold Alloy

Abstract

W. H. METZGER pointed out at a symposium on “Electroless Plating” in 1959 that nickel–phosphorus alloys with amorphous structure were ferromagnetic¹. In a recent publication, S. Mader and A. S. Nowick reported that ferromagnetic cobalt–gold alloys in the composition range 25–60 atomic per cent gold were made amorphous by evaporating the two metals simultaneously on to a sapphire slide which was cooled by liquid nitrogen². These were the first examples of materials being both amorphous and ferromagnetic, although the existence of ferromagnetism in amorphous materials was shown to be possible from theoretical considerations by A. I. Gubanov³. Recently, at this laboratory amorphous fibres of one of these alloys (cobalt 25 atomic per cent gold) were made by rapidly quenching the molten material using an electron beam heating and anvil cooling device⁴.