Interlayer coupling and magnetoresistance in Ir/Co multilayers

Abstract

Fcc(111) oriented Ir/Co multilayers were prepared to study their magnetic and magnetotransport properties. The superlattice structure was characterized by X-ray diffraction. Results measured for magnetization and magnetoresistance (ΔR/R) exhibit an oscillatory interlayer exchange coupling with a period of about 1 nm (4.5 monolayers). The coupling strength JAF and the largest ΔR/R obtained are − 2.05 mJ/m2 and 4% (at 10 K), respectively. The observed oscillatory behavior can be attributed to an interaction of separated Co magnetic layers, which must be some sort of RKKY coupling. Using this concept, we find a match of the measured oscillation period with the relevant wave vector on the Fermi surfaces of Ir.