Magnetic state of Nb(l-7nm)/Cu30Ni70 (6nm) superlattices revealed by Polarized Neutron Reflectometry and SQUID magnetometry

We report results of a magnetic characterization of [Cu30Ni70(6nm)/Nb(x)](20) (x=1 divided by 7nm) superlattices using Polarized Neutron Reflectometry (PNR) and SQUID magnetometry. The study has shown that the magnetic moment of the structures growths almost linearly from H = 0 to H-sat = 1.3kOe which can be interpreted as evidence of antiferromagnetic (AF) coupling of the magnetic moments in neighbouring layers. PNR, however, did not detect any in-plane AF coupling. Taking into account the out-of-plane easy axis of the Cu30Ni70 layers, this may mean that only the out-of-plane components of the magnetic moments are AF coupled.