Observation of nonmonotonic oscillatory interlayer exchange couplingin Co ∕ Cu ∕ Co O films with varying Cu spacer thickness

We report our experimental observation of interlayer exchange coupling phenomena in Co O ∕ Cu ∕ Co trilayers with systematic variation of Cu spacer layer thickness as well as temperature. It has been found that there exists a clear indication of nonmonotonically varying oscillatory interlayer exchange coupling. The amplitude of oscillation increases, reaches to the maximum, and decreases with increasing Cu spacer thickness from 1 to 16 atomic layers for all temperature ranges between 70 and 200 K .