Magnetic and transport properties of amorphous ferro magnetic Gd-Au, Gd-Ni and Gd-Co alloys obtained by splat-cooling

We present the results of magnetization and transport measurements on amorphous Gd80Au20, Gd68Ni32and Gd67Co33alloys over a temperature range of 1.8-300°K in fields up to 75 kOe. These ferromagnetic alloys obtained by splat-cooling have Curie temperatures Tcof 150, 125 and 175°K, respectively. The saturation moment per Gd atom extrapolated to 0°K is estimated to be 7± 0.1 μB. The exchange integrals for Gd-Au and Gd-Ni are determined from the value of Tcand from the temperature dependence of the saturation magnetization. The zero-field resistivity for Gd-Ni and Gd-Co exhibits maxima around Tc. We present some preliminary results of magnetoresistivity measurements with applied field parallel and perpendicular to the foil plane. The anisotropy is in-plane for Gd-Co. For the Gd-Au and Gd-Ni alloys, there is no well-defined easy axis.