Towards a low current Hall effect sensor

•Hall effect sensor works linearly in the microampere regime.•Hall effect sensor signal-to-noise ratio in the microampere regime is similar to the milliampere regime.•From three different current regimes we find the best option.•Very small hysteresis deviations are measured. Many modern electronic devices utilize linear Hall sensors to measure current and the magnetic field, as well as to perform switching and latching operations. Smartphones, laptops, and e-readers all work with very low (sub-milliampere) currents. To perform a switching function in low-power devices, however, Hall sensors must work in the microampere regime. This paper demonstrates, for the first time, the ability of a standard Hall detector to work linearly in the microampere regime between 0 and 0.7 Tesla. To do so, we developed a current source with RMS noise on the order of 10–100 pA/Hz. An optimized electronic circuit with minimal connections feeds current to the Hall sensor, and the Hall voltage is measured with an industrial nanovoltmeter. After cooling this system down to temperatures as low as 77 K, we found mostly 1/f noise. In this regime the thermal noise was negligible. We demonstrate the capabilities of this system by precisely measuring the slope of the Hall effect with a four-point probe at current intensities of 100, 10, and 1 μA. We expect that our system can work as a microampere Hall sensor using external voltage detectors.