Magnetic Interactions in a Weak Moment System:Au−Co

Bulk magnetic measurements have been made on $\mathrm{Au}-\mathrm{C}\mathrm{o}$ (5 and 7 at.%) between 1.5 and 300 °K. The high-temperature susceptibility is compared with that in dilute samples, from which it is concluded that interactions among the Co atoms strengthen the virtual Co moments. This conclusion is confirmed by the low-temperature properties which indicate ordering, e.g., susceptibility maxima, hysteretic magnetization curves, and time- and temperature- dependent remanences. Low-temperature measurements are presented on a strong moment alloy $\mathrm{Au}-\mathrm{F}\mathrm{e}$ 1 at.%. The low-temperature ordered-state properties of the $\mathrm{Au}-\mathrm{C}\mathrm{o}$ and $\mathrm{Au}-\mathrm{F}\mathrm{e}$ specimens are qualitatively, and semiquantitatively, similar.