Oscillatory interlayer coupling with Cu and Zr underlayer thickness for Co/Cu multilayers

Oscillatory behavior (with a period of about 9 nm) of antiferromagnetic coupling with the thicknesses of Cu and Zr underlayers is reported for sputtered Co(1 nm)/Cu(2.3 nm) multilayers. The related oscillation of magnetoresistance is also observed. Based on the analysis of x-ray diffraction patterns, the variation of crystallographic orientation and modulation period is proved not responsible to the phenomenon. But the underlayer strongly affects the growth orientation of multilayer.