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 mi croscope tip was incorporated into a room temperature scanning Hall probe m icroscope system and successfully used for the direct magnetic imaging of m icroscopic domains of low coercivity perpendicular garnet thin films and de magnetized strontium ferrite permanent magnets. At a driving current of 800 muA, the Hall coefficient, magnetic field sensitivity and spatial resoluti on of the Bi probe were 3.3 x 10(-4) Omega /G, 0.38 G/root Hz and similar t o 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/AlGaA s heterostructure micro-Hall probe, which exhibited a value of 0.41 G/root Hz at a maximum driving current of 2 muA.