Magnetic Imaging of Ferromagnetic Domains by Room Temperature Scanning Hall Probe Microscopy using GaAs/AlGaAs and Bismuth Micro-Hall Probes

摘要

Heterostructure GaAs/AlGaAs and bismuth (Bi) micro-Hall probes were integrated into a room temperature scanning Hall probe microscope system (RT-SHPM) for imaging localized magnetic fluctuations at the surfaces of floppy disks, crystalline garnet thin films, and strontium ferrite permanent magnets. As a drive current of 800 μA the sensitivity of the Bi micro-probes was 0.38 G/√ Hz and comparable with the GaAs/AlGaAs probes. Bi nano-Hall probes with an active region of 200 nm * 200 nm were fabricated by focused ion beam milling and successfully used for magnetic imaging of ferromagnetic domains structures. Bismuth was found to be a practical alternative to semiconductors for fabricating ultra-high resolution nanometer scale Hall probes.