Magnetization of the CuMn spin glass in high magnetic fields

High magnetic field (up to 35T) magnetization (M) measurements of five Mn doped Cu spin glass samples measured from above their respective glass temperatures to 4.2K is reported. Three of the samples were polycrystalline with Mn concentrations of 4%, 7%, and 13.5% atomic and two were single crystals with concentrations of 2.6% and 7.92%. The data were fitted to a Brillouin function with a Curie constant (Tc). The fits were performed for all the data for a given M vs H and another set included only those data above 10T; both gave similar results. The most notable feature is the M vs H data were only slightly temperature dependent. This meant the effective T_c varied linearly from +40K for the 13.5% sample to the order of -20K at LHe temperatures for all concentrations. A plot of the Tc values vs T for all the samples is approximately independent of the Mn concentration. The magnetization measurements at a given temperature always followed heating above the glass temperature for a given alloy to the temperature of measurement in zero field. The low field data were highly non-Brillouin like with the initial low field magnetization rising faster than linear up to approximately 5T followed by a significant decrease with increasing field to the order of 10T for all samples.