Differential Surface Acoustic Wave Magnetic Field Sensor With The Balance of Magnetic Field Sensitivity And Temperature Drift

Surface acoustic waves (SAW) magnetic field sensors based on single-port resonator configurations with the advantages of temperature compensation and wireless functionality are promising candidates for magnetic field and electric current wireless sensing applications. In this work, an on-chip integrated single-port differential SAW magnetic field sensor that consists of two SAW resonators based on a Pt/Co 40 Fe 40 B 20 /Ta/Co 40 Fe 40 B 20 /Ta/SiO 2 /quartz multilayered structure is investigated. By designing the SAW propagation directions of the two SAW resonators, one is parallel to the hard axis and the other is perpendicular to the hard axis of magnetization of the Co 40 Fe 40 B 20 films. The magnetic sensitivity of the SAW magnetic field sensor is improved by utilizing the difference frequency between Love wave modes, while the magnetic hysteresis remains low. The temperature drift of the differential SAW magnetic field sensor is suppressed. A magnetic field sensitivity of -2350.4 kHz/mT with a low temperature drift of 1.6 kHz/℃ is achieved. These results are beneficial for the development of temperature compensated SAW magnetic field sensors with high magnetic field sensitivities. • An on-chip integrated single-port differential surface acoustic wave magnetic field sensor consists of two surface acoustic wave resonators. • The magnetic sensitivity of the differential surface acoustic wave magnetic field sensor is improved by utilizing the difference frequency between Love wave modes. • The temperature drift of the differential surface acoustic wave magnetic field sensor is suppressed by utilizing the difference frequency between surface acoustic wave modes.