Magnetoelectric nonlinearity in magnetoelectric laminate sensors

Abstract

High-resolution current sensor utilizing nanocrystalline alloy and magnetoelectric laminate composite Rev. Sci. Instrum. 83, 115001 (2012) A nonlinearity in the magnetoelectric coefficient, a Nonlin ME , of Metglas=Pb(Zr,Ti)O 3 (PZT) and Metglas=Pb(Mg 1=3 ,Nb 2=3 )O 3 -PbTiO 3 (PMN-PT) laminate sensors has been observed. This nonlinearity was found to be dependent on the dc magnetic bias (H dc ) and frequency of the ac drive field (H ac ). The maximum value of a Nonlin ME for both types of composites was found near the electromechanical resonance. For Metglas=PZT laminates, the maximum occurred under a finite bias of H dc %5 Oe; whereas, for Metglas=PMN-PT, the maximum was found near zero dc bias. One application for a Nonlin ME is a cross-modulation scheme that can shift low frequency signals to higher frequency to achieve lower noise floor. For Metglas=PMN-PT, a Nonlin ME has another application: removal of the necessity of a dc bias, which helps to design high-sensitivity sensor arrays and gradiometers.

Piezomagnetic strain-dependent non-linear magnetoelectric response enhancement by flux concentration effect

“…11 Recently, a modulation mode sensor which used a 2nd order ME nonlinearity was reported that transferred low-frequency target signals to higher frequencies. 12 In this method, an exciting carrier signal provided an effective means to reduce 1/f noise, to increase the signal-to-noise ratio (SNR), and to mitigate vibrational noise that is compared to a conventional passive mode scheme. 13 The effectiveness of this frequency transfer ability was proportional to the nonlinear ME coefficient a ME nonlin: Recently, for Metglas/Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 laminates, a ME nonlin was shown to have an optimum value near H dc ¼ 0.…”

High non-linear magnetoelectric coefficient in Metglas/PMN-PT laminate composites under zero direct current magnetic bias

“…Significantly lower equivalent magnetic noise floors have been obtained in this study, consistent with prior predictions. 12 …”

“…[14][15][16] The value of a ME nonlin at H dc ¼ 0 was determined to be 13 V=ðcm À Oe 2 ) for n ¼ 2, which represents an improvement of 6 times over previously reported values. 12 Figure 2(a) shows the linear ME voltage coefficient a ME for the same structures for different values of n. a ME was measured using a lock-in amplifier, as a function of H DC and in response to H AC ¼ 1 Oe at f ¼ 1 kHz that was driven by a Helmholtz coil. With increasing H DC , a ME increased quickly from zero at H DC ¼ 0 to a maximum value at a particular H DC (which is referred as H optim ) and then declined to zero for H DC !…”

“…There have been limited reports for Metglas/piezo-fiber composites that exhibit a ME nonlin on the order of 2.2 V=ðcm À Oe 2 Þ at H DC ¼ 2 Oe under a driving signal of f 0 ¼ 1 kHz, which can be improved to a ME nonlin ¼ 25.3 V=ðcm À Oe 2 Þ by simply optimizing f 0 to be the electromechanical resonant (EMR) frequency. 12 Here, an enhancement of a ME nonlin at H DC ¼ 0 for a Metglas/PMN-PT heterostructure is shown through an optimized Metglas-piezofiber thickness ratio. Of particular importance, the frequency modulation scheme for the non-linear ME effect can shift low frequency signals to higher frequency ones to achieve a reduced noise floor.…”

Structural dependence of nonlinear magnetoelectric effect for magnetic field detection by frequency modulation

“…10 However, to date, all investigations of the nonlinear ME coefficient, which is the physical basis of the frequency modulation method, have been reported using the same laminate structure as that used in the passive mode. 11 Due to a dependence of the different orders of nonlinearity on the magnetostrictive material, the structure resulting in a maximum nonlinear ME coefficient may not be the same as for the linear ME effect used in the passive mode. However, any investigations of the ME laminate structure that optimize the mode have not yet been performed.…”