Room temperature sub-micron magnetic imaging by scanning Hall probe microscopy

An ultra-high sensitive room temperature scanning Hall probe microscope (RT -SHPM) system incorporating a GaAs/AlGaAs micro-Hall probe was used for the direct magnetic imaging of localized magnetic field fluctuations in very c lose proximity to the surface of ferromagnetic materials. The active area, Hall coefficient and field sensitivity of the Hall probe were 0.8 mum x 0.8 mum, 0.3 Omega /G and 0.04G/root Hz, respectively. The use of a semiconduc ting Hall probe sensor enabled measurements in the presence of externally a pplied magnetic fields. Samples studied included magnetic recording media. demagnetized strontium ferrite permanent magnets, and low coercivity perpen dicular garnet thin films. The RT-SHPM offers a simple means for quantitati vely monitoring sub-micron magnetic domain structures at room temperature.