Planar Hall Effect Magnetometer with 5 pT Resolution

We integrate elliptical planar Hall effect (PHE) magnetometers with optimized high permeability magnetic flux concentrators. The integrated magnetometers exhibit at room temperature an equivalent magnetic noise of ∼5 pT/√Hz at 10 Hz, 7.4 pT/√Hz at 1 Hz, and better than 100 pT/√Hz at 10 mHz. The results constitute more than an order of magnitude improvement over previously reported state-of-the-art PHE magnetometers, and demonstrate, for the first time, the ability of a magnetoresistive sensor to match the performance of state-of-the-art, high-end flux-gate, and miniature atomic magnetometers.