Time-dependent susceptibility measurements have been performed on multilayered two-dimensional (2D) 40-Å-wide ${\mathrm{Cu}}_{0.865}$${\mathrm{Mn}}_{0.135}$ spin-glass films, separated by Cu interlayers of width 10<${\mathit{w}}_{\mathrm{il}}$<1200 Å. It is found that samples with ${\mathit{w}}_{\mathrm{il}}$<30 Å display 3D dynamic behavior. For 30<${\mathit{w}}_{\mathrm{il}}$<600 Å a gradual decoupling of the spin-glass layers occurs, and for ${\mathit{w}}_{\mathrm{il}}$≥600 Å typical 2D behavior is observed. The effect of a finite interlayer coupling on the dynamic susceptibility is a distinct crossover from 2D dynamic behavior at short observation times to 3D dynamic behavior at long times. A clear influence on the spin-glass dynamics is still observable for interlayer thicknesses of order 500 Å; i.e., multilayered spin-glass films are extremely sensitive probes of the effective range of Ruderman-Kittel-Kasuya-Yosida interaction mediated via metallic interlayers. The results also yield information on the relation between time scale and length scale in relaxation experiments, a fundamental concept of domain theories of the spin-glass phase.

• Received 13 March 1991

DOI:https://doi.org/10.1103/PhysRevB.44.4410