Detection of magnetic domain wall of YIG with scanning diamond NV center probe

Probing and imaging of the magnetic domain structure at the nanoscale are important to understand the basic physics of the magnetic interaction, and for the application in the spintronics field. The nitrogen-vacancy (NV) center; spin state of a defect structure in diamond, is attracting much attention for its novel spin sensing ability at nanoscale and room temperature conditions. We developed a scanning NV center spin sensing probe combined with atomic force microscopy (AFM) based on quartz tuning-fork resonator. Electron spin resonance (ESR) signal from the apex of the NV center probe can be detected optically (optically detected magnetic resonance, ODMR) via confocal microscope setup. A diamond probe (φ 4 µm, length 10 µm) hosting an ensemble of NV centers is glued at the end of the AFM probe enabling simultaneous measurements of the ESR and topographic images of the sample. Magnetic insulator of yttrium iron garnet (YIG) was used for the magnetic film sample that shows magnetic domain wall structures with a micrometer scale under zero external magnetic field. The stray magnetic field from magnetic domain walls was measured with the scanning NV center probe.