Layer resolved magnetization reversal study in SmCo₅/Fe nanocomposite bilayers

A hard/soft SmCo₅/ Fe nanocomposite magnetic bilayer system is fabricated on x-ray transparent 100--200 nm thin Si₃N₄ films by magnetron sputtering. The microscopic magnetic domain pattern and its behaviours during magnetization reversal in the hard and the soft magnetic phases are studied separately by element specific magnetic soft x-ray microscopy at a spatial resolution of better than 25 nm. We observe that the domain patterns for the soft and hard phases show coherent behaviours in varying magnetic fields. We derive local M(H) curves from the images of Fe and SmCo₅ separately and find the switches for hard and soft phases to be the same.