Three-axis cryogenic Hall sensor

Magnetic field measurements are very important for magnetic and superconducting material research. Hall sensors have many advantages for these measurements. They can also be used for magnetic field profile measurements, which provide information about material homogeneity. We have developed a three-axis Hall system which consists of three perpendicular InSb Hall sensors for operation at room as well as cryogenic temperatures. The active area of each sensor is 50 x 50 mu m(2). It is located at the corner edge of the substrate and is suitable for detecting the spatial field profile within a cube of 225 x 225 x 225 mu m(3). The sensitivity of the sensor is of the order of 20 mV/T and the offset voltage is < 50 mu V for a nominal control current of 10 mA. The problems of detecting the 3D field components using planar Hall sensors and the oscillatory signal behaviour due to quantum effects are discussed.