High-Sensitivity Wideband Magnetic Field Sensor Using Nonlinear Resonance Magnetoelectric Effect

A wideband ac magnetic field sensor using the nonlinear magnetoelectric effect of magnetic fields mixing in a planar structure consisting of a piezoelectric langatate and an amorphous ferromagnet has been described. The measured and pumping fields mix due to nonlinearity of the ferromagnetic layer magnetostriction. The voltage of the total frequency generated by the langatate layer is recorded at the frequency of the structure planar acoustic oscillations that provide both frequency selectivity and enhancement of the voltage by Q ≈ 1400. The maximum sensitivity of the sensor is 1.8 V/Oe, which is ~320 times higher than the sensitivity of the sensor using the linear magnetoelectric effect, but ~4 times lower than the sensitivity of the linear sensor at the resonance. The sensor operates without a dc bias magnetic field and allows registration of fields as low as ~10-5Oe in the frequency band of 1-70 kHz with a frequency resolution of ~50 Hz.