Magnetoelectric Voltage Research Articles

Artificial synaptic device based on a multiferroic heterostructure

A type of synaptic devices have been constructed by employing the nonlinear magnetoelectric effects in multiferroic materials. The state of the magnetoelectric coefficient of the device can be tuned continuously with a large number of nonvolatile levels by engineering the applied electric-field pulses. Therefore, the magnetoeletric coefficient may be regarded as the synaptic weight, and the subsequent magnetoelectric voltage VME acts as excitatory or inhibitory postsynaptic potentials. Synaptic behaviors including the long-term potentiation, long-term depression, and spiking-time-dependent plasticity have been demonstrated in a multiferroic heterostructure made of Metglas/PMN-PT/Metglas. The consumed energy density is estimated to be ~7.7 mJ cm−3 per spike, comparable to the biological synapse in the brain. Our work presents an alternative way towards artificial synaptic devices with very low energy consumption.

Face-shear 36-mode magnetoelectric composites with piezoelectric single crystal and Metglas laminate

A magnetoelectric (ME) composite is designed with a face-shear 36-mode PMN-PZT single crystal and a Metglas laminate structure to enhance the ME coupling properties and exhibit single resonance behavior over a wide-frequency range. The off resonance and resonance ME voltage coefficients of the designed-composite are high, and approximately 90% similar to those of the 32-mode. While the 32-mode has multiple resonance, the electromechanical and magnetoelectric resonance spectra of the 36-mode composite exhibit only a single resonance over a wide-frequency range from 50 to 200 kHz making it suitable for detecting specific frequency magnetic fields. In addition, it is highly sensitive, being able to detect a magnetic field down to 2 pT at resonance (103 kHz), and therefore has potential to replace conventional bulky and costly magnetic field sensors.

Design, analysis, and optimization of a magnetoelectric actuator using regression modeling, numerical simulation and metaheuristics algorithm

In this study, a new method was proposed for the design of composite magnetoelectric actuator. Design of experiment (DOE) was utilized to investigate the mutual effect of geometric parameters. Moreover, the effect of impedance phase angle, magnetic field, and bias field were studied through finite element (FE) modeling. Resonance frequency, displacement value, magnetoelectric coefficient, and mode shape were considered as response variables. Analysis of variance (ANOVA), regression modeling and response surface method (RSM) were used to investigate the pair-wise effect of input parameters on the response variables. ANOVA results showed that the magnetoelectric length and piezoelectric thickness are the most important parameters affecting the magnetoelectric performance. The optimization process was performed using Metaheuristics algorithm. Optimum results were verified using magnetoelectric measurement setup and Laser Doppler Vibrometry device. The accuracy of the FE model in resonance frequency prediction was estimated at 97%. The prediction error of the FE model for the magnetoelectric voltage parameter was 14.6%, which was about 12.9% better than the regression model. The confirmation test showed that the regression modeling can only predict magnetoelectric behavior and for determining magnetoelectric performance, a precise FE model would be more reliable. Such proposed optimization technique can be used in the design of magnetoelectric composites.

Effect of co-sintering time on magnetoelectric response of Pb0.895Sr0.06La0.03(Zr0.56,Ti0.44)O3 multilayer–Ni0.6Zn0.4Fe2O4 composite fabricated by tape casting

The effect of cosintering time on magnetoelectric (ME) behavior of Sr, La doped lead zirconate titanate multilayer–nickel zinc ferrite composites fabricated by the tape-casting method has been investigated. Powders of individual phases, viz., Pb(1 − x − 3y/2)SrxLay(Zrz,Ti(1 − z))O3 (PSLZT) and Ni0.6Zn0.4Fe2O4 (NZFO), were prepared by the solid-state reaction method, and their respective thick films were fabricated by the tape-casting method. A PSLZT multilayer having Pt inner electrodes stacked onto NZFO laminated composites was cosintered at 1060 °C for 1–10 h. Cosintered, warpage-free, and delamination-free layered composite thick film structures were analyzed by scanning electron microscopy. Microstructure at the interface could be crucial for better magnetoelectric coupling, and, hence, the microstructure of the interface was analyzed as a function of sintering time at a fixed sintering temperature. Elemental mapping revealed a negligible interdiffusion between PSLZT and NZFO phases. Composites cosintered for different time durations were analyzed for their ferroelectric behavior. Further, impedance spectrum analysis indicated clear resonance behavior for the composites cosintered for 2 and 6 h. All the composites were analyzed for magnetoelectric properties at different applied DC magnetic fields having a superimposed ac magnetic field of a fixed frequency and different ac frequencies at fixed DC magnetic fields. The magnetoelectric coefficient was found to increase with an increase in the sintering time of up to 6 h and an ME coefficient of 230 mV/cm Oe with a self-bias nature. Magnetoelectric resonance behavior was also studied, which showed an ME voltage coefficient of 6 V/cm Oe for composites sintered for 6 h at resonance.

Transparent Magnetoelectric Materials for Advanced Invisible Electronic Applications

AbstractThe need for flexible and transparent smart materials is leading to substantial advances in principles, material combinations, and technologies. Particularly, the development of optically transparent magnetoelectric (ME) materials will open the range of applications to new directions such as transparent sensors, touch display panels, multifunctional flat panel displays, and optical magnetic coatings. In this work, a flexible and transparent ME composite is made of magnetostrictive Fe72.5Si12.5B15 microwires and piezoelectric poly(vinylidene fluoride‐trifluoroethylene). The high magnetostriction of Fe72.5Si12.5B15 (35 ppm) enables superior ME voltage response (65 mV cm−1 Oe−1) obtained at the critical longitudinal magnetic field equating the transverse anisotropy (14500 A m−1) on the external shell of the microwire.

Room temperature magnetoelectric coupling and relaxor-like multiferroic nature in a biphase of cubic pyrochlore and spinel

The search for multiferroic order in a single phase of bismuth pyrochlore has been unsuccessful so far. In this direction, our study unveiled the capability of a biphase of bismuth pyrochlore and spinel in hosting a multiferroic order at room temperature. A complex oxide biphase of cubic pyrochlore and cubic spinel crystals acquired in the Bi2O3-Nb2O5-2MnCO3-Fe2O3 system revealed the crystals of a spinel phase (Fe1.59(3)Mn1.39(3)O4.26(7)) intergrown in the dense pyrochlore (Bi1.35(1)Fe0.64(1)Nb1.26(1)Mn0.75(1)O6.39(5)) matrix. The average composition of the components of the investigated biphase was determined using an electron probe microanalyzer (EPMA). The structural features indicated the presence of large ionic displacements within the cubic pyrochlore phase as seen from the appearance of 442 reflection in the X-ray diffraction pattern and infrared active mode at ∼64 cm−1 in the Raman spectrum recorded at room temperature. The pyrochlore single-phase composition (Bi1.35(1)Fe0.64(1)Nb1.26(1)Mn0.75(1)O6.39(5)), as suggested from a thorough EPMA microstructural analysis, exhibited broad dielectric relaxation and an overall paramagnetic behavior. The observation of disordered superparamagnetism as well as dielectric relaxation in the biphase conformed to that of a relaxorlike multiferroic behavior at room temperature. Moreover, self-biased magnetoelectric voltage coefficients of 0.60 mV/cm Oe at 100 Hz and 5.54 mV/cm Oe at 1 kHz were detected between magnetization and electric polarization at room temperature. Therefore, the composite of such a pyrochlore and spinel with an inherent property of strong spin–orbit and spin–lattice coupling will be interesting from theoretical and experimental point of view in the arena of magnetoelectrics.

Magnetoelectric Zn0.2Co0.8Fe2O4-PbZr0.58Ti0.42O3 nanocomposite for bistable memory and magnetic field sensor applications

Abstract The spinel ferrite based nanocomposite (Zn0.2Co0.8Fe2O4-PbZr0.58Ti0.42O3) has been prepared through a chemical process to observe the magnetoelectric and memory effect at room temperature. The structural and surface characterization of the nanoparticles reveal the presence of both the phases having crystallites size in nanometric regime, which are uniformly distributed. The observed nonlinear behaviour of the current of magnetic field dependent current-voltage characteristic may be due to the oxygen vacancy and defect states at the grain boundaries of the granular system. The sharp increased in nature of current is attributed to the space charge polarization and the space charge limited current determining through Child’s law. The maximum value of current is found to ~60 μA in presence of 15 V at ~2 kOe. Moreover, the change of open circuit current is found to ~71% in magnetic field. The DC electrical property of the nanocomposite shows two separate resistance states. Furthermore, the magnetic field dependent resistance is varying with an applied electric field and vice-versa. These features are a demonstration of good magnetoelectric coupling between the piezoelectric and piezomagnetic order parameters. The magnetoelectric coupling coefficient of the nanocomposite may be attributed to the magnetostriction properties of the piezomagnetic phase. The magnetoelectric coupling coefficient is largely depending on the direction of an applied magnetic field for the directional dependent magnetostriction properties of the piezomagnetic phase. The maximum value of the coupling coefficient has been found to ~4.5 mV/cm-Oe at room temperature. Furthermore, an applied AC magnetic field dependent magnetoelectric voltage coefficients of the nanocomposite have been estimated, which is completely matched with an observed value. This nanocomposite demonstrates the presence of memory effect, resistive switching behaviour, magnetoelectric coupling, etc.

Doping induced modification in magnetism and magnetoelectric coupling at room temperature in Fe2Te(1-x)NbxO6

The polycrystalline Fe2TeO6 (FTO) and Fe2Te(1-x)NbxO6 [x = 0.5 (FTON5), x = 0.10 (FTON10)] is prepared via solid state reaction route. Comparative structural study is done by the Rietveld refinement of the powder X-ray diffraction data of all the prepared samples. We observe the presence of ferroelectricity in FTO via remanent polarization versus electric field (PE) hysteresis loop measurement with remanent polarization ∼4.85 nC/cm2. On application of 1.2 T external magnetic field, this observed remanent polarization changes 60% which confirms the presence of magnetoelectric (ME) coupling in the material. The magnetic field dependent PE loops also confirms the presence of ME coupling in both FTON5 and FTON10. In case of FTON10 the remanent polarization changes by 80% on application 1.2 T. The presence ME coupling is also observed through the nonlinear magnetoelectric voltage response on application of modulated DC magnetic field in both FTO and FTON5. This nonlinear voltage response changes to linear behavior for FTON10 due to Nb doping.

Enhance magnetoelectric coupling in xLi0.1Ni0.2Mn0.6Fe2.1O4–(1 − x)BiFeO3 multiferroic composites

Lead-free multiferroic composites of xLi0.1Ni0.2Mn0.6Fe2.1O4 (LNMFO)–(1 − x)BiFeO3 (BFO) were prepared. Multiferroic properties of LNMFO–BFO were analyzed. The compositions are a combination of ferrite and perovskite phases verified by the measurement of X-ray diffraction. FESEM image analyzed the surface morphology of the compositions. The EDX Spectroscopy performed quantitative elemental of the compositions. The $$\mu_{i}^{\prime }$$ increases in the samples with ferrite concentration. Dielectric properties were analyzed with frequency. The change in $$\varepsilon^{\prime }$$ with frequency displays dielectric dispersion in the low frequency zone because of interfacial polarization of Maxwell–Wagner type resulting from the two phase interface. Frequency autonomous behavior of the $$\varepsilon^{\prime }$$ is seen in the higher frequency region as electric dipoles can not follow the rapid change in the alternating electrical field. The $$\varepsilon^{\prime }$$ is reduced with ferrite concentration. Dielectric loss peaks occur when the electrons hopping frequency is almost equal to the applied field frequency. The $$\sigma_{AC}$$ of the samples follows the power law of Jonscher and increases with frequency, indicating that there is conduction of small polaron hopping. Impedance spectroscopy studies recommend that the grain and grain boundary perform to the conduction phenomena. Magnetization was measured to study the recompose of the ferrite phase with the magnetic field. Both $$M_{s}$$ and $$M_{r}$$ have been increased with ferrite content. The magnetoelectric voltage coefficient is reduced with ferrite concentration. The maximum value of the magnetoelectric voltage coefficient is quite high, up to ~ 98 × 103 Vm−1 T−1 for the composite 0.1LNMFO–0.9BFO.

Magnetoelectric composite films of La0.67Sr0.33MnO3 and Fe-substituted Bi4Ti3O12 fabricated by chemical solution deposition

Magnetoelectric composite layered films of La0.67Sr0.33MnO3 (LSMO) and Fe-substituted Bi4Ti3O12 (Bi4Ti3-xFexO12, BiTFx, x = 0.05, 0.10, 0.15 and 0.20) were fabricated on a LaNiO3-buffered silicon substrate by chemical solution deposition method. The LaNiO3 layer with c-axis orientation can not only induce the oriented growth of the overlaying LSMO and BiTFx layers, but also can act as an electrode material for electric measurements. The Fe-substituted content has a significant effect on the surface morphology of BiTFx phase, and leakage, dielectric and ferroelectric properties of the BiTFx/LSMO films. The BiTF0.10/LSMO composite film exhibits an improved leakage performance, the highest dielectric constant and the best ferroelectric properties. Furthermore, an interesting finding is that a weak ferromagnetism is present in the BiTF0.10 phase. The first-principle calculations suggest that the spin-resolved total density of states for BiTF0.10 are asymmetric, which can induce spin splitting and magnetic moments. The BiTF0.10/LSMO film also exhibits excellent magnetoelectric coupling performance, and its magnetoelectric coupling response is sensitive to AC magnetic frequency. The highest magnetoelectric coupling voltage coefficient can reach up to 47.5 V/cm·Oe without the presence of DC bias magnetic field.

Magnetoelectric hysteresis of a bilayered magnetoelectric composite

A bilayered magnetoelectric composite has been fabricated by bonding a magnetostrictive layer Terfenol-D and a piezoelectric layer Pb(Zr0·52Ti0·48)O3 together. The magnetoelectric hysteresis behavior of the magnetoelectric composite has been investigated. The results show that the magnetoelectric voltage coefficients of the composite are strongly affected by the bias magnetic field and test period. The magnetoelectric voltage coefficients with the bias magnetic field exhibit hysteresis over a test period, forming hysteresis loops with an anticlockwise direction sweep. The test time hysteresis caused by a fast varying bias magnetic field can be reduced by prolonging the test period. The observed coercive field, remanence and ratio of the remanence of the magnetoelectric hysteresis loops with the test period obey an exponential decay law. In addition, the bias magnetic field dependence of magnetoelectric hysteresis loops is found to be associated with magnetic hysteresis loops. These findings provide some ideas not only for practical applications, but also for the magnetoelectric effect examinations of magnetoelectric composites.

NiFe2O4 - ZnO semiconducting nanocomposites: Studies of room temperature magnetoelectric coupling and electronic transport

Nanocomposites of xNiFe2O4 – (1-x)ZnO (x = 0.2, 0.3 and 0.5) have been prepared through chemical “pyrophoric reaction process”. Structural characterizations confirm the formation of both NiFe2O4 and ZnO phases in nanocomposites. The room temperature magnetoelectric coupling, dielectric and temperature dependence of electrical properties of the prepared nanocomposites have been investigated. The observed magnetoelectric coupling may be owed to the field dependent magnetostriction property of the piezomagnetic phase of the nanocomposites. The magnetoelectric voltage is measured in both transverse and longitudinal directions. Electrical transport studies are carried out using an ac impedance spectroscopy and dc resistivity techniques. Metal-semiconductor transition of the nanocomposites has been explained on the light of delocalized and localized charge carrier. Detailed analysis of ac conductivity with frequency at varying temperature suggests the thermally activated electronic transport conduction mechanism for large and small polaronic hopping in the nanocomposites. The semiconducting band gap of the nanocomposites has also been estimated using recorded absorbance spectra. Light-dependent current-voltage characteristics are non-Ohmic in nature and exhibit significant electrical memory effect with resistive switching. On light illumination, there is a significant decrement in current with quenching of hysteresis loop suggesting high recombination of the photo-generated carriers.

Multiferroicity in Mg-doped ZnO nanoparticles

Zn1-xMgxO (x = 0.0, 0.03, 0.06, 0.09, 0.12, 0.15) nanoparticles have been synthesized using hydroxyoxalate type precursor by simple chemical precipitation method. X-Ray diffraction (XRD) study reveals that the nanoparticles crystallize in the hexagonal wurtzite structure in the space group P63mc with (1 0 0) being the preferred growth plane. The average crystallite size of the compounds acquired from XRD and TEM analyses are nearly identical with values around 30 ± 5 nm. The doped samples, with reported ferromagnetic properties, are found to have ferroelectric properties. The magneto-electric (ME) voltage coefficient of the multiferroic samples is found to have appreciable values and increases with increase in doping concentration.

Modeling of a Magnetoelectric Laminate Ring Using Generalized Hamilton's Principle.

The mathematical modeling of the magnetoelectric (ME) effect in ME laminates has been established for some simple structures. However, these methods, which are based on the differential equation approach, are difficult to use in other complex structures (e.g., ring structures). In this work, a new established approach based on the generalized Hamilton’s principle is used to analyze the ME effect in an ME laminated ring. Analytical expressions for ME voltage coefficients are derived. A comparison with the conventional method indicates that this approach is more convenient when the modeling analysis is performed on complex structures. Further, experimental data are also obtained to compare with the theoretical calculations in order to validate the new approach.

Specific Features of the Magnetoelectric Effect in Permendur–Quartz–Permendur Structures in the Region of Electromechanical Resonance

The experimental frequency and field dependences of the magnetoelectric effect in three-layer permendur–quartz–permendur structures in the region of electromechanical resonance were studied. It was found that the magnetoelectric voltage coefficient and the Q-factor of these structures in the resonance region are much higher than those of similar structures based on lead zirconate titanate. Anomalous behavior of the field dependences of the magnetoelectric voltage coefficient and the Q-factor was observed in the region of electromechanical resonance. This feature is attributable to the negative ΔE effect.

Investigation of magnetoelectric effect in Bi0.5Na0.5TiO3–CoMn0.2Fe1.8O4 composites

In the present work Bi 0.5 Na 0.5 TiO 3 (BNT) and CoMn 0.2 Fe 1.8 O 4 (CMFO) composites, (1-x) BNT/(x) CMFO with x = 0.10, 0.20, 0.30, 0.40 and 0.50 have been synthesized using solid state reaction method. X-ray diffraction exhibits the peaks akin to constituent BNT and CMFO phases suggesting the effective development of the desired composites. The variation of dielectric constant with temperature reveals their diffuse phase transition behaviour and existence of two dielectric anomalies in vicinity of ferroelectric to antiferroelectric and from antiferroelectric to paraelectric transition temperatures. Remnant polarization (2P r ) and Coercive field (2E C ) found to decrease with addition of CMFO. Furthermore, magnetization vs. magnetic field (M-H) hysteresis loops shows an increment in magnetization with increase in CMFO content. Complex impedance spectroscopy confirms the existence of grain (bulk) effect and temperature dependent electrical relaxation processes in the composites. Magnetoelectric analysis shows maximum magnetoelectric voltage coefficient, α ME for x = 0.10 and the value of, α ME decreases from 6.765 mV/cm-Oe to 2.780 mV/cm-Oe for the composites x = 0.10 to 0.50.

Experimental Investigation of the Magnetoelectric Effect in NdFeB-Driven A-Line Shape Terfenol-D/PZT-5A Structures

In this paper, the magnetoelectric (ME) effect is investigated in two kinds of A-line shape Terfenol-D/PZT-5A structures by changing the position of the NdFeB permanent magnet. The experimental results show that both ME composite structures had multiple resonance peaks. For the ME structure with acrylonitrile-butadiene-styrene (ABS) trestles, the resonance peak was different for different places of the NdFeB permanent magnet. Besides, the maximum of the ME coefficient was 4.142 V/A at 32.2 kHz when the NdFeB permanent magnet was on top of the Terfenol-D layer. Compared with the ME coefficient with a DC magnetic field, the ME coefficient with NdFeB magnets still maintained high values in the frequency domain of 65~87 kHz in the ME structure with mica trestles. Through Fourier transform analysis of the transient signal, it is found that the phenomenon of multiple frequencies appeared at low field frequency but not at high field frequency. Moreover, the output ME voltages under different AC magnetic fields are shown. Changing the amplitude of AC magnetic field, the magnitude of the output voltage changed, but the resonant frequency did not change. Finally, a finite element analysis was performed to evaluate the resonant frequency and the magnetic flux distribution characteristics of the ME structure. The simulation results show that the magnetic field distribution on the surface of Terfenol-D is non-uniform due to the uneven distribution of the magnetic field around NdFeB. The resonant frequencies of ME structures can be changed by changing the location of the external permanent magnet. This study may provide a useful basis for the improvement of the ME coefficient and for the optimal design of ME devices.

Structural Effects of Magnetostrictive Materials on the Magnetoelectric Response of Particulate CZFO/NKNLS Composites.

In this study, magnetostrictive powders of CoFe2O4 (CFO) and Zn-substituted CoFe2O4 (CZFO, Zn = 0.1, 0.2) were synthesized in order to decrease the optimal dc magnetic field (Hopt.), which is required to obtain a reliable magnetoelectric (ME) voltage in a 3-0 type particulate composite system. The CFO powders were prepared as a reference via a typical solid solution process. In particular, two types of heterogeneous CZFO powders were prepared via a stepwise solid solution process. Porous-CFO and dense-CFO powders were synthesized by calcination in a box furnace without and with pelletizing, respectively. Then, heterogeneous structures of pCZFO and dCZFO powders were prepared by Zn-substitution on calcined powders of porous-CFO and dense-CFO, respectively. Compared to the CFO powders, the heterogeneous pCZFO and dCZFO powders exhibited maximal magnetic susceptibilities (χmax) at lower Hdc values below ±50 Oe and ±10 Oe, respectively. The Zn substitution effect on the Hdc shift was more dominant in dCZFO than in pCZFO. This might be because the Zn ion could not diffuse into the dense-CFO powder, resulting in a more heterogeneous structure inducing an effective exchange-spring effect. As a result, ME composites consisting of 0.948Na0.5K0.5NbO3–0.052LiSbO3 (NKNLS) with CFO, pCZFO, and dCZFO were found to exhibit Hopt. = 966 Oe (NKNLS-CFO), Hopt. = 689–828 Oe (NKNLS-pCZFO), and Hopt. = 458–481 Oe (NKNLS-dCZFO), respectively. The low values of Hopt. below 500 Oe indicate that the structure of magnetostrictive materials should be considered in order to obtain a minimal Hopt. for high feasibility of ME composites.

Effect of CoFe2O4 weight fraction on multiferroic and magnetoelectric properties of (1 − x)Ba0.85Ca0.15Zr0.1Ti0.9O3 − xCoFe2O4 particulate composites

Different compositions of the composite lead-free multiferroic magnetoelectric systems are fabricated by employing piezoelectric Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) and magnetostrictive CoFe2O4 (CFO) by varying the CFO weight fraction. The magnetic, dielectric, ferroelectric and magnetoelectric (ME) properties of the system are analyzed and found to be varying with the ferrite concentration. Even though the composite systems exhibit high magnetocapacitance (MC) properties (~ 35%), the possible stray contributions from magnetoresistance and magnetostriction make it unreliable for the quantitative determination of ME coupling coefficient (MECC). Therefore, a dynamic method is chosen for the measurement of magnetoelectric coupling. All the compositions have shown fairly good ME coupling. It is found that the ME coupling increases with ferrite fraction and the highest ME coupling of 14.8 mV/(cm Oe) is observed for 0.6BCZT–0.4CFO composite. It is also observed that the ME voltage increases linearly with the ac modulating field with a voltage generation of 1.25 V/cm (for x = 0.4) for a small ac modulating field of 100 Oe. This high sensitivity and linear response of ME coupling to the ac magnetic fields offer the possibility of employing these particulate composites for a wide range of applications from magnetic field sensors to energy harvesters.

The effects of the soft magnetic alloys’ material characteristics on resonant magnetoelectric coupling for magnetostrictive/piezoelectric composites

The resonant magnetoelectric (ME) effects are investigated in Terfenol-D/PZT laminates with various soft magnetic alloys (i.e. FeCuNbSiB, FeSiB and CoNiFeSiB). The soft magnetic alloys with high magnetic permeability and magnetization produces an additional magnetostatic field in the Terfenol-D, which changes the effective magnetic field distribution within the Terfenol-D and plays an important role at the large zero bias ME response. Meanwhile, the magnetostrictive strain of soft magnetic alloys can produce a pre-stress on the Terfenol-D layer due to its low saturation field, which enhances the maximum ME voltage coefficient and reduces the required optimal dc magnetic field Hopt,dc. The experimental results indicate that the largest zero bias ME voltage coefficient is obtained for Terfenol-D/PZT composite with FeCuNbSiB (i.e. the soft magnetic alloy with the highest magnetization), which is about 7.3 times more than that of Terfenol-D/PZT at zero bias. The maximum ME voltage coefficient is obtained for Terfenol-D/PZT composite with FeSiB (i.e. the soft magnetic alloy with the largest magnetostriction constant) at Hopt,dc = 175 Oe, which is about 1.15 times greater than that of Terfenol-D/PZT composite (at Hopt,dc = 598 Oe) and also happens at a much smaller bias field.