Studying Influence of Normal Metal on Magnetic Properties of Y₃Fe₅O₁₂ Thin Film Locally Using Scanning Ferromagnetic Resonance Force Microscopy

We image the boundary separating regions of altered internal magnetic fields in Y₃Fe₅O₁₂(YIG) thin films arising from patterning metal films on the YIG film surface. High quality YIG thin films have proven to be useful for spintronics research. However, detailed investigations of internal magnetic variations in patterned devices are still lacking. Spatial maps of the internal fields were acquired using ferromagnetic resonance force microscopy(FMRFM); a technique allowing for nano to micro-scale spatial resolution and high sensitivity to magnetic fields within the film. FMRFM scans laterally across the YIG-YIG/M (M = Au, Pt) boundary indicate an internal field step that is tens of Gauss. Micromagnetic simulations assuming the presence of uniaxial anisotropy in both the bare YIG and the YIG/M bilayer qualitatively match experimental measurements. We discuss possible physical causes of this field shift, methods used to image the spatial magnetization profile, and implications for future spintronic devices.