Magnetic susceptibility of Au:Dy dilute alloys

The magnetic susceptibility of dilute Au:Dy alloys has been measured from 1.55 to 300 K for Dy concentrations of 14 200, 7100, 2800, and 1300 ppm. The apparent Weiss constant varies from - 1.8 K to zero, within experimental error, over the concentration range. A least-squares fit to the susceptibility data results in a ${\Gamma }_7$ ground doublet at the two higher concentrations (as reported by Murani for a 15 000-ppm sample), and in a ${\Gamma }_8^{\mathrm{}\left(1\right)\mathrm{}}$ ground quartet at the two lower concentrations, the latter in agreement with (500-1000 ppm) EPR data. The dilute-limit crystalline-field parameters $C_4=-24.8\mathrm{}$ K, $C_6=3.61\mathrm{}$ K were extracted from the fit to the susceptibility data.