Magnetic-Order Transition in Thin Fe Overlayers on Cr: Role of the Interfacial Roughness

The distribution of magnetic domains in a thin Fe overlayer on Cr is calculated as a function of the coverage thickness in the presence of roughness at the interface. The spin-polarized electronic structure is determined by solving self-consistently a d -band model Hamiltonian in the mean-field approximation. Arising from a magnetic multidomain arrangement, a zero total magnetic moment is obtained when starting the Fe deposition. A transition towards a single Fe domain at a critical coverage thickness leads to a net magnetization in qualitative agreement with various experimental observations. This macroscopic magnetic behaviour is traced back to environment-dependent microscopic properties such as the local magnetic moments and magnetic ordering.