Finite size effects in a metallic spin glass (invited)

Abstract

We have observed finite size effects in thin films (20 Å<L<1000 Å) of CuMn with concentrations of 4%, 7%, and 13.5% Mn. In order to have measurable magnetization the samples are produced in the form of multilayers with silicon or copper interlayers. The interlayers are sufficiently thick (tSi =70 Å; tCu =300 Å) so that there are no observable interactions between the CuMn layers. The samples are characterized structurally by low-angle x-ray diffraction, imaging, and x-ray fluorescence using a scanning transmission electron microscope. The metallic films are also characterized by measuring the electrical resistivity of both multilayer and single-layer CuMn samples. The temperature Tg of the peak in the dc susceptibility shifts with film thickness L as (T0g−Tg)/T0g∼L−λ for all concentrations and for both Si and Cu interlayers. The results for 4% Mn will be discussed in detail and compared with previously published data on 7% Mn.