Local and bulk magnetic properties of liquid quenched amorphous GdCo and GdNi alloys

The NMR measurement on amorphous GdCo and GdNi alloys was performed to investigate the contribution of the Co hyperfine field. The amorphous ribbons of nominal composition Gd60Co40, Gdsub(63.5)Cosub(36.5), Gd67Co33, Gd67Ni29Co4 were prepared by melt-spinning in argon atmosphere. The amorphous nature of the samples were checked by X-ray scanning. The Curie temperatures for amorphous Gd2Ni and Gd2Co were found to be 125 and 175 K, respectively. The Curie temperature rose rapidly with increasing Co content. The saturation magnetization at 4.2 K for the amorphous Gd65Ni35, Gd67Co33, and Gd60Co40 was 220.3, 219.0, and 200.3 emu/g, respectively. The spin-echo NMR spectra were taken. It can be concluded that the Co hyperfine fiels in Gd67Co33 is positive, and the low-field contribution in Gd60Co40 is positive. A strong positive CEP (and orbital) contribution is suggested. (Kato, T.)