Checkerboard pattern of the interlayer coupling between two Co films across Fe/Cu and Cu/Co/Cu spacer layers grown on Cu(100)

Quantum well (QW) states and oscillatory interlayer coupling in Co/Cu/Fe/Co/Cu(001) are investigated by angular resolved photoemission spectroscopy and x-ray magnetic linear dichroism. We find that the QW states in Cu/Fe/Co/Cu(001) depend very little on the magnetic state of the fcc Fe films. The interlayer coupling between the Co films across the Cu/Fe spacer layer displays a checkerboard pattern in Fe-Cu thickness plane. The presence of the fcc Fe ferromagnetic live layer at the Cu/Fe interface is shown to be responsible for the checkerboard pattern, which was confirmed by experiments on Co/Cu/Co/Cu/Co/Cu(100) system.