SHORT-PERIOD OSCILLATION OF THE INTERLAYER EXCHANGE COUPLING IN THE FERROMAGNETIC REGIME IN CO/CU/CO(100)

A unique sample was prepared on a Cu(100) single crystal, consisting of three Co layers separated by two Cu layers in the form of wedges oriented perpendicular to each other: Cu(100)/80 angstrom Co/Cu wedge A/30 angstrom Co/Cu wedge B/30 angstrom Co/7 angstrom Cu/30 angstrom Au. Position-sensitive magneto-optical Kerr effect measurements along Cu wedge B, at a fixed position on Cu wedge A corresponding to maximum antiferromagnetic (AF) coupling, enabled us to investigate not only the AF but also the ferromagnetic (F) coupling between the two 30 angstrom Co layers as a function of the Cu thickness. The measurements confirmed both long and short period coupling oscillations in the AF regime, and revealed the predicted extension of the short period through the F regime.