Magnetoresistivity and oscillatory interlayer magnetic coupling of sputtered Fe/Nb superlattices

Abstract

Sputtered Fe(20 \AA{})/Nb superlattices were prepared with Nb thicknesses ranging from \ensuremath{\sim}2 to 40 \AA{}, and oscillatory interlayer magnetic coupling was observed by means of magnetoresistance (MR), magnetometry, and Kerr rotation measurements. As many as five oscillations between ferromagnetic and antiferromagnetic coupling were observed at room temperature with a Nb periodicity of \ensuremath{\sim}9 \AA{}. The largest negative MR measured, however, was only 0.3%. The low MR values of high resistivity (60--120 \ensuremath{\mu}\ensuremath{\Omega} cm) suggest that the structural disorder associated with the lattice mismatch (13% in this system) plays an important role in governing the transport phenomenon.