An estimation of the magnetic disorder at Fe/Cr interfaces in coupled and non-coupled Fe/Cr multilayers

The antiferromagnetic coupling at the Fe/Cr interfaces, inferred from the orientation of the Cr magnetic moments, is used to estimate the magnetic disorder resulting from the interfacial roughness in Fe/Cr multilayers. A crossover from in-plane to out-of-plane orientation of Cr moments depends on the energy cost in either case: (i) to break the interfacial Fe–Cr antiferromagnetic coupling or (ii) having sites with frustrated Cr–Cr antiferromagnetic coupling in the Cr interlayers. A quantitative model of the magnetic frustration due to interfacial disorder in Fe/Cr multilayer systems is described. The step edge density, or terrace size, required to break the interfacial Fe–Cr coupling and destroy the Fe–Fe interlayer exchange coupling is estimated.