The Ultra‐Low Power 3D Graphene‐Based Magnetic Impedance Sensor with the Planar Structure

ABSTRACT The three‐axis magnetometers are widely utilized in automotive electronics, industrial robotics, and intelligent navigation for motion recognition and attitude detection. But the conventional 3D magnetic field detection is realized with multiple orthogonal sensors, causing the spatial errors, non‐orthogonality, and bulky issue. This study presents an ultra‐low power 3D magneto‐impedance (MI) sensor based on a planar [FeSiBC 20 nm/Cu 6 nm] 50 /graphene microcoil/[FeSiBC 20 nm/Cu 6 nm] 50 heterostructure. Utilizing the synergetic effects of soft magnetic material's magnetoimpedance and graphene's Hall effect under the weak current excitation, it decouples the X, Y, Z magnetic field components in one measurement, avoiding the multiple steps required by the recent planar sensors. It possesses the ultra‐low power of 25 µW, high resolutions of 20, 20, 7587 nT/Hz 1/2 at the X, Y, Z direction, and real‐time detection capability. Experiments verify that the miniature sensor array improves the magnetic field imaging accuracy by around 65% compared to the conventional 1D Hall sensors in the magnetic field leakage test.