Direct magnetic imaging of ferromagnetic domain structures by room temperature scanning hall probe microscopy using a bismuth micro-hall probe

A bismuth micro-Hall probe sensor with an integrated scanning tunnelling microscope tip was incorporated into a room temperature scanning Hall probe microscope system and successfully used for the direct magnetic imaging of microscopic domains of low coercivity perpendicular garnet thin films and demagnetized strontium ferrite permanent magnets. At a driving current of 800 muA, the Hall coefficient, magnetic field sensitivity and spatial resolution of the Bi probe were 3.3 x 10(-4) Omega /G, 0.38 G/root Hz and similar to 2.8 mum, respectively. The room temperature magnetic field sensitivity of the Bi probe was comparable to that of a semiconducting 1.2 mum GaAs/AlGaAs heterostructure micro-Hall probe, which exhibited a value of 0.41 G/root Hz at a maximum driving current of 2 muA.