SWITCHING AND REENTRANT BEHAVIOR OF MAGNETIZATION IN ULTRATHIN FILMS OF FCC CO UPON DEPOSITION OF CU

We analyse the easy magnetisation axis ''switching'' recently discover ed in experiments on Co ultrathin films with a deposited submonolayer of Cu by ab initio methods. The present large-scale calculations show that the nanomagnetic pattern of a stepped Co(001) surface 2-3 monolay ers thick with submonolayer quantities of Cu has a complex three-dimen sional character. We show that the maximum non-collinearity of spin-di rections is about 30 degrees, and the ''switching'' has a re-entrant c haracter as a function of Cu coverage.