Diffusion of muons in metallic multilayers

The development of the low energy muon beam at PSI opens the possibility of studying muon diffusion in artificially layered structures within the nm scale. Here, we report on first muon diffusion experiments on different Cr/x nm Au/Cr trilayers (x=19,21,30,39) in the temperature range from 5 to 320 K. If the appropriate implantation energy is chosen, the initial muon implantation profile is centered within the non-magnetic Au layer. Muons stopping in magnetic Cr or penetrating the Au/Cr interface by thermally activated diffusion immediately lose their spin polarization. The depolarization of the LE-μSR signal allows extraction of the time-dependent fraction of muons reaching one of the interfaces