Ultrasensitive flexible magnetoelectric sensor

Abstract

Ever-evolving advances in flexible magnetic sensors are promising to fuel technological developments in the fields of touchless human–machine interaction, implantable medical diagnosis, and magnetoreception for artificial intelligence. However, the realization of highly flexible and extremely sensitive magnetic sensors remains a challenge. Here, we report a cost-effective, flexible, and ultra-sensitive heterostructural magnetoelectric (ME) sensor consisting of piezoelectric Pb(Zr0.52Ti0.48)O3 (PZT) thick films and Metglas foils. The flexible sensor exhibits a strong ME coefficient of 19.3 V cm−1 Oe−1 at low frequencies and 280.5 V cm−1 Oe−1 at resonance due to the exceptionally high piezoelectric coefficient d33 ∼ 72 pC N−1 of the constituent PZT thick films. The flexible ME sensor possesses not only ultrahigh sensitivities of 200 nT at low frequencies and 200 pT at resonance but also shows an excellent mechanical endurance. Through 5000 bending cycles (radii of ∼1 cm), the sensors showed no fatigue-induced performance degradation. This ultrasensitive flexible sensor provides a platform capable of sensing and responding to external magnetic fields and will find applications in soft robotics, wearable healthcare monitoring, and consumer electronics.

Magnetoelectric Magnetic Field Sensors: A Review

“…Comparison of the data in this table shows that in the low-frequency region, the most sensitive of the presented ME magnetic field sensors are those described in [ 46 , 47 , 48 , 49 , 62 ], and in resonance mode is a sensor based on bidomain LN y +140°/Metglas 2826 MB [ 60 ] and the sensor described in [ 50 ]. In practice, the most important characteristic of ME magnetic field sensors is the equivalent magnetic noise.…”

“…The characteristics of the studied structure suitable for the magnetic field sensor design are considered in the example of one of the papers. Nana Yang et al in [ 46 ] report on the study of an ultra-sensitive ME heterostructural sensor consisting of Metglas/Pb(Zr 0.52 Ti 0.48 )O 3 (PZT thick films with a thickness of 2.2 µm), the distinctive properties of which are flexibility and cost-effectivity. The piezoelectric material has the extremely great piezoelectric coefficient d 33 of about 72 pC/N for PZT thick films.…”

“… Flexible ME laminate structure. Reprinted with permission from [ 46 ]. Copyright 2012 AIP Publishing.…”

“… Magnetic field sensitivity and linear response of the flexible Metglas/PZT laminated ME sensor to the AC magnetic field at bias field of 4.5 Oe ( a ) at the frequency of 1018 Hz and ( b ) at the resonant frequency of 54 kHz. Reprinted with permission from [ 46 ]. …”

Review of Magnetoelectric Sensors

“…Compared with singlephase ME material, ME heterostructures and ME laminates perform greatly enhanced coupling capability, which is generally characterized by ME coefficient α ME [7][8][9]. After a development of nearly half a century, tremendous progress regarding ME composites and related device applications has been reported [1][2][3]6,[10][11][12][13][14][15][16][17][18][19].…”