Magnetic coupling in sputtered Fe/Si-type multilayers

In HV-sputtered Fe100-xSix/Si100-yFey multilayers the antiferromagnetic coupling strength and the fraction of ferromagnetic coupling increases with decreasing temperature. The ferromagnetic component can be explained by bridging along grain boundaries or by an Fe percolation mechanism in the nonmagnetic interlayers. Recent speculations that the magnetic coupling across the FeSi spacers is mediated by thermal excitation of charge carriers are incompatible with our observations