Evidence of dimensional crossover of the spin-glass transition in thinCuMn multilayers

Abstract

We have used high-quality ${\mathrm{Cu}}_{92}$ ${\mathrm{Mn}}_8$/${\mathrm{Al}}_2$ ${\mathrm{O}}_3$ multilayers to investigate the shift in temperature and the change in scaling behavior of the spin-glass transition as a function of the layer thickness. In the thinnest CuMn layers (60 and 88 Å), the spin-glass exponents determined from the nonlinear susceptibility shift to new values, distinctly different from those for the bulk. These exponents are consistent with numerical studies of 2D spin-glass systems, suggesting that a 3D to 2D crossover occurs.