Scaling of nonlinear susceptibility in MnCu and GdAl spin-glasses

SQUID measurements of susceptibility χ versus field H are fitted by χ=χ0-χ1Ha-1 at a given temperature T, for two classic spin-glasses: 4.6% Mn in Cu (polycrystalline) and 37% Gd in Al (amorphous). χ1(T) shows a much stronger anomaly than χ0(T), while a (T) has a minimum at the freezing temperature Tf. The data can also be scaled according to χ0-χ= H2δf((T-Tf)H2) with δ=5±1 and =4.5±0.5. © 1981 The American Physical Society.