Enhancing the sensitivity of magnetoelectric sensors by increasing the operating frequency

Abstract

Articles you may be interested inEnhanced sensitivity in magnetoelectric current-sensing devices with frequency up-conversion mechanism by modulating the magnetostrictive strain J. Appl. Phys. 115, 17E505 (2014) We present a field modulation technique that increases the operating frequency of magnetoelectric (ME) sensors so that it can match the mechanical resonance frequency of the sensor. This not only improves the sensitivity but also reduces the effect of 1/f noise that is inherent at low frequencies. The technique, which is shown to apply to both symmetric and asymmetric ME sensors, relies on the strong, nonlinear magnetic field dependence of the magnetostriction. The combination of a lower 1/f noise and enhanced response at resonance has increased the signal to noise ratio of a symmetric sensor by two orders of magnitude. The detection limit of this sensor was lowered from 90 to 7 pT/ ffiffiffiffiffi ffi Hz p at 1 Hz in a magnetically unshielded environment.

Note: Self-biased magnetic field sensor using end-bonding magnetoelectric heterostructure

“…[1][2][3][4] Thus, the ME composite offers an alternative type of magnetic sensor. [8][9][10][11][12][13][14][15] However, because of the magnetic-field dependency of the piezomagnetic coefficient, ME field sensors typically require a DC bias field to maximize sensitivity that increases power consumption, volume, and costs. [1][2][3][4][8][9][10][11][12][13] In addition, the magnetostrictive and piezoelectric phases in traditional laminate composites are bonded with interfacial epoxy layers, so the different phases couple each other by shear forces.…”

“…[8][9][10][11][12][13][14][15] However, because of the magnetic-field dependency of the piezomagnetic coefficient, ME field sensors typically require a DC bias field to maximize sensitivity that increases power consumption, volume, and costs. [1][2][3][4][8][9][10][11][12][13] In addition, the magnetostrictive and piezoelectric phases in traditional laminate composites are bonded with interfacial epoxy layers, so the different phases couple each other by shear forces. [1][2][3][4] But to control the shear modulus, the thickness and the perfection of the interfacial epoxy layer between magnetostrictive phase and piezoelectric phase are troublesome and complex operation.…”

Нелинейное Преобразование Магнитного Шума В Магнитоэлектрической Структуре

“…При этом нелинейная зависимость магнито-стрикции ФМ-слоя λ от магнитного поля приводит к ряду нелинейных эффектов. Так, под действием гармонического поля накачки h( f ) и постоянного поля смещения H структура генерирует электрическое напряжение u( f ) на частотах гармоник [2][3][4][5][6], под действием бигармони-ческой накачки она генерирует напряжения с суммарной и разностной частотами [7,8], обнаружена статическая деформация структур в пере-менном поле [9]. До сих пор нелинейные МЭ-эффекты в композитных структурах наблюдали только в условиях гармонической накачки.…”

Effect of excitation mode on the magnetic field detection limit of magnetoelectric composite cantilevers

“…14 This has involved research to increase the effect size of the ME response, e.g., materials, effects of device geometry and operation modes, [15][16][17][18] resonance-enhancement and loss mechanisms, 13 and investigation of noise effects and their behavior including the Johnson-Nyquist noise [19][20][21][22][23] from dielectric losses in piezoelectric materials 24 in ME cantilevers and electronics, noise in magnetostrictive (MS) materials, and thermal vibration noise. 23,[25][26][27][28] Different operation modes investigated for low frequency biomagnetic field sensing 14 include (1) direct detection, where magnetic fields oscillating at the cantilever resonance directly excite magnetostrictivepiezoelectric strain coupling and resonance-enhanced signals; (2) modulation techniques, [29][30][31] where signal fields are detected as sidebands to a carrier as a result of frequency mixing in non-linear functional materials; and (3) the ΔE effect, 32,33 where the field dependence of the elastic modulus in magnetostrictive materials is used. Effect size and noise behavior differ greatly with operation mode.…”