Strong and Weak Interlayer Exchange Coupling in V/Fe Multilayers

The $d_{V}-V$/0.6 nm-Fe multilayers with constant thickness sublayers were prepared onto naturally oxidised Si(100) substrate using UHV (5× $10^{-10}$ mbar) DC/RF magnetron sputtering. Results showed that the saturation field of the V/Fe multilayers oscillate with antiferromagnetic interlayer exchange coupling peaks near the V spacer thickness of about 1.3, 1.6, 2.05 nm. Furthermore, all the samples with vanadium layer thickness near local maxima of the antiferromagnetic coupling show zero remanence. The short period of the antiferromagnetic peak oscillations is due to indirect Ruderman-Kittel-Kasuya-Yosida (RKKY)-type coupling of the Fe layers across vanadium spacer. The absence of the antiferromagnetic peaks in the very strongly coupled region (below $d_{V}$ ≈ 1 nm) could be explained by direct ferromagnetic exchange coupling of the Fe layers due to magnetic polarization of V atoms near V-Fe interface.