SCANNING HALL PROBE MICROSCOPY OF SUPERCONDUCTORS AND MAGNETIC-MATERIALS

We describe results from a scanning Hall probe microscope operating in a broad temperature range, 4-300 K. A submicron Hall probe manufactur ed in a GaAs/AlGaAs two-dimensional electron gas is scanned over the s ample to measure the surface magnetic fields using conventional scanni ng tunneling microscopy positioning techniques, The magnetic field str ucture of the sample together with the topography can be obtained simu ltaneously, The technique is noninvasive with an extremely low self-fi eld of < 10(-2) G and yields a quantitative measurement of the surface magnetic field in contrast to magnetic force microscopy. in addition the microscope has an outstanding magnetic field resolution (similar t o 1.1 x 10(-3) G/Hz at 77 K) and high spatial resolution, similar to 0 .85 mu m, Images of individual vortices in a high-T-c Y1Ba2Cu3O7-gamma thin film at low temperatures and magnetic domains in an Fe-garnet cr ystal at room temperature are presented. (C) 1996 American Vacuum Soci ety.