High Sensitivity Planar Hall Effect Magnetic Field Gradiometer for Measurements in Millimeter Scale Environments

We report a specially designed magnetic field gradiometer based on a single elliptical planar Hall effect (PHE) sensor, which allows measuring magnetic field at nine different positions in a 4 mm length scale. The gradiometer detects magnetic field gradients with equivalent gradient magnetic noises of similar to 958, similar to 192, similar to 51, and similar to 26 nT/m root Hz (pT/mm root Hz) at 0.1, 1, 10, and 50 Hz, respectively. The performance of the gradiometer is tested in ambient conditions by measuring the field gradient induced by electric currents driven in a long straight wire. This gradiometer is expected to be highly useful for the measurement of magnetic field gradients in confined areas for its small footprint, low noise, scalability, simple design, and low costs.

Automated summary

The article describes a magnetic field gradiometer based on a single elliptical planar Hall effect sensor, capable of measuring magnetic fields at different positions within a small scale. It demonstrates good performance at various frequencies and shows promise in practical testing scenarios.