METALLIC AND SEMICONDUCTOR HALL MICROPROBES FOR WIDE TEMPERATURE RANGE APPLICATIONS

We report on mesoscopic Hall sensors allowing accurate magnetization studies of submicron or nanometer-sized samples over a wide temperature range. Even at 300 K, the probes can reliably resolve local changes in dc field of ≈ 1 G with spatial resolution of ≈ 1 μm, which corresponds to a flux sensitivity of less than 0.1 ϕ 0 (ϕ 0 =h/e is a flux quantum). The resolution increases 100 times at temperatures below 80 K. The capabilities of new micromagnetometers are demonstrated by measuring nm-scale movements of individual domain walls in a ferromagnet.