Optimization of U-shaped Cu@ Fe20Ni80 core for orthogonal fluxgate sensor

Magnetic fluxgate sensors require composite ferromagnetic probes with excellent noise performance. An electrochemical deposition method was employed to deposit various thicknesses of permalloy (Fe20Ni80) onto copper wires with varying diameters. The magnetic properties of the composite structural filaments were then characterized. A U-shaped magnetic core structure was created for application in an orthogonal fluxgate sensor. Through noise testing in fundamental mode, we determined the optimal diameters and thicknesses of copper and permalloy. By analyzing the magnetization mechanism, probe sensitivity, and noise value at 1 Hz in response to changes in the excitation signal, we established that a probe consisting of a 100 mu m Cu core and 12 mu m Fe20 Ni80 coating [Cu(1 0 0)-FeNi(12)] demonstrated the optimal noise performance at 1 Hz, with a figure of merit of 59 pT/root Hz. The proposed structure meets the requirements of most practical applications. The results can serve as a valuable reference for the fabrication of subsequent composite structure wire magnetic sensor probes.