Investigations of CoNi patterns for VBL-stabilization in micromagnetic memories by wall resonance

When bars of hard magnetic material like CoNi are used to stabilize pairs of vertical Bloch lines (VBLs) in a VBL memory, it is important to determine the local magnetic properties of the bars. A CoNi film with insufficient coercivity was used to demonstrate the potential usefulness of wall resonance spectroscopy for investigations of the coupling between topological structures and the domain wall with high spatial resolution. The measurements demonstrate that the shape of the wall resonance spectra (WRS) derived from a 4-μm-long wall section between two bars allows quantitative and qualitative determination of the magnetization state of the VBL confinement