Imaging interfaces defined by abruptly varying internal magnetic fields by means of scanned nanoscale spin wave modes

Abstract

Nanoscale devices fabricated out of magnetic heterostructures are central to the emerging field of spintronics, so understanding of magnetization dynamics at interfaces between dissimilar materials is essential. Here we report local imaging of magnetization dynamics at the interface formed by a sharp discontinuity in the magnetic properties of a ferromagnetic thin film using localized mode ferromagnetic resonance force microscopy (FMRFM). The behavior of the localized modes near the interface evolves with increasing magnitude of the FMRFM probe field due to its competition with the steplike internal demagnetizing field. We use micromagnetic modeling to visualize the evolution of the localized mode as the magnetic probe is scanned across the interface. Our results demonstrate the ability to image sharp changes in internal magnetic properties in nanoscale devices and provide insights into the mechanisms underlying the generation and manipulation of localized modes near the interface, thus providing a new tool for microscopic studies of spin transport across magnetic interfaces and spin dynamics in their vicinity.