Periodic enhancement of the electron-electron interactions and the magnetoresistance in magnetic Co/(Cr/Ag)/Co multilayers

Electrical transport and magneto-optical Kerr effect have been measured on Co/(Cr/Ag)/Co multilayers in which the thickness A of the bimetallic nonmagnetic spacer Cr/Ag varies from 0 to 35 Angstrom. The measurements clearly indicate the presence of antiferromagnetic coupling for 9 < lambda < 23 Angstrom. At low temperatures (T < 20 K), the resistivity shows a logarithmic increase which is most probably caused by the two-dimensional electron-electron interactions. The magnitude of the log(10) T term and of the negative magnetoresistance varies periodically with a period corresponding approximately to one monolayer of Cr.