Cantilever magnetoelectric PZT/Tb–Fe–Co resonators for magnetic sensing applications

Magnetoelectric material-based cantilever resonators have been considered as a promising solution for magnetic sensing applications. However, most applications focus on bulk piezoelectric (e.g., PZT) laminated composites, which put a critical limit for miniaturizing into micrometer-sized devices. This work aims at demonstrating the potential of a micro-resonator approach with lower power consumption and smaller size. It reports on the fabrication and characterization of a resonant cantilever based on a freestanding multi-ferroic PZT/Tb–Fe–Co thin film multilayer, where the magnetic signal is sensed by measuring the shift of the device resonant frequency. The Tb–Fe–Co layer acts as a magnetic field sensing layer, while the PZT thin film integrated in the capacitor geometry acts as a micro-transducer to obtain an electrical signal. For a magnetic field less than 0.2 T, a sensitivity as high as 487 Hz/T is measured for the sensor under a vacuum environment. While the sensor design has to be further optimized to improve the performance, it is promising as a micro-magnetoelectric sensor for magnetic field sensing.