Curvature and Stress Effects on the Performance of Contour‐Mode Resonant ΔE Effect Magnetometers

Abstract

Miniaturized piezoelectric/magnetostrictive contour‐mode resonators are effective magnetometers by exploiting the ΔE effect. With dimensions of ≈100–200 µm across and <1 µm thick, they offer high spatial resolution, portability, low power consumption, and low cost. However, a thorough understanding of the magnetic material behavior in these devices is lacking, hindering performance optimization. This manuscript reports on the strong, nonlinear correlation observed between the frequency response of these sensors and the stress‐induced curvature of the resonator plate. The resonance frequency shift caused by DC magnetic fields drops off rapidly with increasing curvature: about two orders of magnitude separate the highest and lowest frequency shift in otherwise identical devices. Similarly, an inverse correlation with the quality factor is found, suggesting a magnetic loss mechanism. The mechanical and magnetic properties are theoretically analyzed using magnetoelastic finite‐element and magnetic domain‐phase models. The resulting model fits the measurements well and is generally consistent with additional results from magneto‐optical domain imaging. Thus, the origin of the observed behavior is identified and broader implications for the design of nanomagnetoelastic devices are derived. By fabricating a magnetoelectric nanoplate resonator with low curvature, a record‐high DC magnetic field sensitivity of 5 Hz nT–1 is achieved.

Intelligent Clothing Design and Data Acquisition under the Scientific Graphics Programming Combined with Wearable Multisensor

“…However, this tool has a drawback; the magnetic field environment of the object is interfered by the ferromagnetic substances. But the plus point of the said tool is that the measured value is stable without serious drift and random interference [10]. e sensor fusion algorithm in this work is to fuse the data of magnetometer and accelerometer and then measure the attitude angle of human body to correct the gyroscope.…”

Modeling and Parallel Operation of Exchange-Biased Delta-E Effect Magnetometers for Sensor Arrays

“…The reproducibility of sensor elements can be considerably impaired by the relaxation of small stress during fabrication [60] and by small variations in the resonator geometry. The condition f ex = f r cannot be fulfilled simultaneously for all N sensor elements because both mechanisms cause a distribution in resonance frequency f r .…”

Modeling and Parameter Sensitivity Improvement in ΔE-Effect Magnetic Sensor Based on Mode Localization Effect

“…The ΔE-effect refers to the phenomenon that the elastic modulus of the magnetostrictive material changes with magnetization due to magnetoelastic coupling, which generally occurs in different components of the elastic stiffness tensor [ 17 , 18 ], and the change of the component adds additional magnetostriction strain [ 19 ]. The ΔE-effect magnetoelastic sensors are most commonly based on resonant structures, especially cantilevers with a ferromagnetic layer ranging from 100 nm to 2 µm [ 20 , 21 , 22 , 23 , 24 ], which are electrically actuated near the resonant frequency through a piezoelectric layer. For the operating mode among the cantilever-type magnetic sensors utilizing the ΔE-effect, there are the first- and second-order bending modes [ 22 ], the torsion mode [ 18 ], contour mode [ 21 ], and surface acoustic resonators [ 25 ] for the magnetic sensitivity improvement.…”

“…The ΔE-effect magnetoelastic sensors are most commonly based on resonant structures, especially cantilevers with a ferromagnetic layer ranging from 100 nm to 2 µm [ 20 , 21 , 22 , 23 , 24 ], which are electrically actuated near the resonant frequency through a piezoelectric layer. For the operating mode among the cantilever-type magnetic sensors utilizing the ΔE-effect, there are the first- and second-order bending modes [ 22 ], the torsion mode [ 18 ], contour mode [ 21 ], and surface acoustic resonators [ 25 ] for the magnetic sensitivity improvement. In earlier years, doubly clamped Metglas resonators [ 26 ] have a sensitivity of 4.7 Hz/T under a 0.7 mT DC bias.…”

“…In earlier years, doubly clamped Metglas resonators [ 26 ] have a sensitivity of 4.7 Hz/T under a 0.7 mT DC bias. Among the recent developments, a representative nanoplate contour mode sensor [ 21 ] obtained a high DC magnetic field sensitivity at 5 Hz/nT. Various ΔE-effect sensors [ 20 , 23 , 24 ] have shown the ability to detect both low- frequency and amplitude (<1 nT) magnetic fields.…”