Significance of the low-field magnetization maximum of a spin-glass nearTg

When the low-field magnetization of a spin-glass is analyzed within the framework of a scaling assumption for the order parameter, three kinds of very different qualitative behaviors are found for the maximum of the magnetization, depending on the value of the critical exponent $\beta$. These different behaviors seem to be found experimentally among the various existing spin-glass systems. The ability of scaling hypotheses to describe the spin-glass transition is questionable as long as physical reasons are not given to justify the absence of universality for the critical behavior of these systems (even as near to one another as $\mathrm{Ag}\mathrm{Mn}$ to $\mathrm{Cu}\mathrm{Mn}$).