Spin-glass transition of a dilute Ag-Mn alloy in a magnetic field

The spin-glass state in a magnetic field is studied in a very dilute Ag-Mn sample containing 150 ppm of Mn. The field-cooled magnetization of this system is investigated over temperatures ranging from 4 down to 0.01 K in magnetic fields from 932 to 1 Oe. Scaling is observed in the nonlinear susceptibility above TG and in the order parameter below TG. The critical exponents are in good agreement with those obtained on much-higher-concentration spin glasses and are different from the mean-field values. There is strong evidence for a phase transition.