Micron-sized Hall probes on a Si/SiGe heterostructure as a tool to study vortex dynamics in high-temperature superconducting crystals

We describe the fabrication of micron-sized Hall probes from a Si/SiGe heterostructure. The magnetic field response of the Hall probes shows a very high sensitivity of similar to 60 Ohm/kG. Below a temperature of 80 K, the Hall probes exhibit a highly linear field dependence of the Hall resistance. The onset of the quantum Hall effect at very low temperatures and high magnetic fields causes only small deviations from the linear field response. We demonstrate the performance of the device as a sensitive local magnetization probe in high-temperature superconducting crystals of Bi2Sr2CaCu2O8. With a linear array of Hall probes we track both the spatial and temporal evolution of the magnetization profile across the crystal. In this way surface and bulk contributions to the overall magnetization can be delineated. (C) 1999 American Institute of Physics. [S0034-6748(99)01603-2].