Frequency conversion in magnetoelectric composites for quasi-static magnetic field detection

We present the detection of quasi-static magnetic fields in Metglas/piezofiber magnetoelectric (ME) composites through frequency conversion. The nonlinear coefficient over wide frequency range (1–30 kHz) was measured, and the noise behavior at sideband was also studied. It was found that the major part of the sideband noise originated from the driven current. Due to the characteristic of the driven current, the sideband noise increased with the increase of the frequency. The ME sensor exhibited excellent performance at low frequencies, sensitivities of 10 mHz, 100 mHz, and 1 Hz were 200 pT, 150 pT, and 20 pT, respectively.