Magnetoelectric Performance Research Articles

An effective strategy for the development of multiferroic composite nanostructures with enhanced magnetoelectric coupling performance: a perovskite-spinel approach.

An energy efficient move toward the regulation of magnetization vector solely with E-field by developing multiferroic (MF) magnetoelectric (ME) nanostructures' have opened up vast avenues for novel low power consumption memories and magnetoelectric devices. The present study delineates the development of multiferroic nanocomposites (MF NCs) with perovskite BiFeO3 and spinel NiFe2O4. A simple Pechini one-pot method is employed for the preparation of nanocomposites with different molar concentrations and the modified structural, magnetic, dielectric, and magnetoelectric performance of NCs is carried out at room temperature. The purity in the crystalline phase of BiFeO3 and NiFe2O4 in the NCs are corroborated by XRD and FTIR spectroscopy, which is further substantiated, while EDAX analysis pointed out the elemental composition. The SEM images provide an evidence for the closely compacted and agglomerated grains with some voids in the prepared sample. A well saturated magnetic hysteresis (M–H) loop reveals long range ferromagnetic ordering and the remanence value ascertains the multidomain structure. The dielectric performance and impedance analysis imparts greater knowledge of the dependence of grain and grain boundaries on the resistive and conductive behavior of the composites. The frequency dependence of electric modulus and impedance exhibits a non-Debye type of relaxation process. The P–E hysteresis loops clearly show the lossy behavior of the composites with an increase in the NiFe2O4 concentration. The ME coupling coefficient of the composites evaluated using the dynamic magnetic field method demonstrates the effective coupling interaction between ferroelectric (FE) perovskite BiFeO3 and ferromagnetic (FM) spinel NiFe2O4. Thus, the findings disclose a greater potential for innovative applications in spintronics and information technology.

A Superhydrophobic Droplet-Based Magnetoelectric Hybrid System to Generate Electricity and Collect Water Simultaneously.

Traditional electromagnetic generators used in hydraulic power generation are heavy, bulky, and immovable, and are thus unsuitable for low water supply. A portable miniature electromagnetic system that can harvest energy from rainwater is critical for developing a sustainable energy strategy. In this study, a superhydrophobic droplet-based magnetoelectric hybrid system is fabricated, that can generate electricity from tiny water droplets. The magnetoelectric system (MS) comprises three parts: a superhydrophobic surface containing a conductive coil, liquid droplets, and a superhydrophobic magnetic powders/Ecoflex base. The mechanical impact of a falling water droplet onto the assembled system is transformed into electricity. Maxwell numerical simulation is used to analyze the related mechanism; the magnetoelectric performance is further improved by modifying the process parameters such as droplet falling velocity and magnetic powder contents. Furthermore, a model is developed, comprising the MS and a cactus-like superhydrophobic patterned plate that can generate electricity and collect water from fog, simultaneously. The described magnetoelectric strategy is believed to enhance and extend functions in energy harvesting and provide a generalized method to exploit new systems toward sustainable energy development.

Effect of sintering temperature on magnetoelectric properties of PbTiO3/NiFe2O4 composite ceramics

ABSTRACT Magnetoelectric composites have attracted much attention due to their strong magnetoelectric coupling effect. In this paper, PbTiO3-NiFe2O4 (PTO/NFO) composite ceramics were prepared by sol-gel method. Effect of sintering temperatures on the structure, dielectric properties and multiferroic properties were studied. XRD results show that PTO/NFO ceramics have been successfully prepared. When the sintering temperature is 1050 °C, the secondary phase PbO2 exists in the ceramics. SEM results show that there were two kinds of grains with different sizes. EDS analysis suggested that the large particles are NFO and the small particles are PTO. The sintering temperature has a great influence on the dielectric and ferroelectric properties of the prepared ceramics. When the sintering temperature is 950 °C, the ceramics show the maximum dielectric constant at low frequency. When the sintering temperature is 1150 °C, the maximum residual polarization is 1.236 μC/cm2. The conductive mechanism of ceramics is dominated by Space Charge – Limited Conduction. The remanent magnetization and coercive field decrease with increasing the sintering temperature. The magnetoelectric coupling coefficient shows that ceramics have strong magnetoelectric coupling performance (5.7 V/cm·Oe).

Giant magnetoelectric effects in serial-parallel connected Metglas/PZT arrays with magnetostrictively homogeneous laminates

Abstract To ensure the magnetostrictive softness, the homogeneity, the decrease of the shear-lag effect and the space-saving construction of narrowed longitudinal-transverse L-T magnetoelectric (ME) composites, a novel parallel-connected-multi-bars (PCMB) geometry of PZT/Metglas is proposed and investigated by simulation and experiment. In this case, Metglas layers are structured in different geometries from the conventional single bar (c-SB) to conventional separated multiple bars (c-SMB), elongated separate multi-bar (e-SMB) and n-magnetic-bar based PCMB (n-PCMB). This n-PCMB geometry divides the conventional ME configuration into n parallel-connected ME units (n-PCMEU) according to the magnetic geometries. The optimal ME performance with the largest ME voltage coefficient αE of 630 V/cm.Oe is achieved in PCMEU with two Metglas bars (n = 2). The ME voltage coefficient can be further enhanced by integrating m of these optimal PCMEUs in series to form a serial-parallel ME unit array m-S (n-PMEU)A. The αE value increases by a factor of 3.6 and reaches 2.238 kV/cm.Oe for 4-S (2-PMEU)A, a factor that is almost equal to m. The resulting 4-S (2-PMEU)A sensor possesses an extremely high sensitivity of 18.1 μV/nT, with a resolution of 10−1 nT.

Annealing heating rate dependence of microstructure and multiferroic properties in Bi4Ti2.9Fe0.1O12/CoFe2O4 layered magnetoelectric composite films prepared by chemical solution deposition method

Lead-free magnetoelectric composite films of CoFe2O4 (CFO) and Bi4Ti2.9Fe0.1O12 (BTF) were prepared on the LaNiO3-coated Si substrate by chemical solution deposition. Though the CFO layer randomly grows on the LaNiO3 layer, the oriented growth of the BTF layer can be regulated by rapid annealing treatment. The results indicated that the annealing heating rate significantly affects the c-axis orientation of the BTF layer, thereby resulting in obvious changes in microstructure, leakage behavior, dielectricity and ferroelectricity of the BTF/CFO films. The BTF/CFO film prepared at the heating rate of 40 °C/s presents the most compact structure, minimum leakage current, maximum dielectric constant and the highest residual polarization of 28.8 μC/cm2. Moreover, the excellent magnetoelectric coupling performance along with the highest magnetoelectric coupling voltage coefficient αE of 20.1 V/cm∙Oe can be achieved in these conditions.

Magnetoelectric Coupling in Epitaxial Multiferroic BiFeO3–BaTiO3 Composite Thin Films

Herein, the magnetoelectric (ME) performance of epitaxial multilayer composite films built from nanometer‐thick layers of multiferroic BiFeO3 and ferroelectric BaTiO3 is reviewed. A successful implementation of shadow‐mask pulsed laser deposition considerably reduces the interface and surface roughness of the multilayers. In dependence of double‐layer thickness and the degree of structural perfection, the multilayers show high ME voltage coefficients up to 480 V cm−1 Oe−1 at 300 K and 0 T bias magnetic field. With decreasing double‐layer thickness, an interface‐driven effect critically enhances the ME coupling in this strain and charge–comediated system. Interestingly, the characteristics of temperature and DC magnetic field dependencies of magnetoelectric voltage coefficients change with the transition from the 2D to 3D character of the single layers, i.e., for BiFeO3 layers thicker than 5 nm within the multilayers. These changes are attributed to variations of the contributing ME coupling mechanisms. Furthermore, scanning transmission electron microscopy (STEM) with energy‐dispersive X‐ray (EDX) spectroscopy mapping‐based nanoanalysis indicates that chemical effects at the interfaces play an important role for the ME performance of the BiFeO3–BaTiO3 multilayer thin films.

Study on magnetoelectric properties of Ni0.5Zn0.5Fe2O4/Ba0.8Sr0.2TiO3 composite ceramics based on Bi2O3 as combustion aid

Ni0.5Zn0.5Fe2O4/Ba0.8Sr0.2TiO3 (NZFO/BST) composite ceramics with different additions of Bi2O3 (0%, 1%, 3%, and 5% wt) were synthesized via the solid-phase sintering method. XRD analysis indicates that the composite ceramics show bi-phase structure, without apparent secondly phases can be observed. SEM images show that all the specimens have relative dense structure, the grain size is in the range 1–2 μm. A certain amount of Bi2O3 is beneficial to grain growth, the average grain size of NZFO/BST ceramics increases from 179 to 297 nm when the concentration of Bi2O3 is 0 and 3%, respectively. EDS results indicate that the distribution of NZFO phase and BST phase is not uniform. The sample NZFO/BST-3%Bi2O3 not only has the largest dielectric constant (er) in the whole temperature range (25–500 °C), but also presents the smallest dielectric loss (tanδ) at high temperature region (> 400 °C), and the maximum tanδ value is less than 0.4 for all the samples, indicating excellent dielectric performance. Compared with other samples, the specimen NZFO/BST-3%Bi2O3 has the largest remnant polarization (~ 1.14 μC/cm2). The sample NZFO/BST-3%Bi2O3 has the largest leakage current density, while the ceramic NZFO/BST-5%Bi2O3 presents the opposite behavior, the value of leakage current of the sample NZFO/BST-3%Bi2O3 is about 7 times larger than that of the specimen NZFO/BST-5%Bi2O. All the composite ceramics show soft magnetic behavior, since Bi2O3 is a non-magnetic phase, addition of Bi2O3 will dilute the magnetic moment per unit volume so as to decrease the magnetic properties of the ceramics. The sample NZFO/BST-3%Bi2O3 has the second largest saturation magnetization (Mr) of 11.27 emu/g and the smallest coercive field (HC) ~ 3.54 Oe. All the samples show strong magnetoelectric coupling effect, the highest magnetoelectric coupling coefficient is ~ 47 Vcm−1Oe−1, which was obtained in the sample without addition of Bi2O3. In short, the addition of Bi2O3 not only affects the structure of composite ceramics, but also plays an important role in affecting the magnetoelectric performance.

Enhanced self-bias magnetoelectric effect in locally heat-treated ME laminated composite

This study reports the improvement in the magnetoelectric (ME) coupling effect in a locally heat-treated FeBSi (Metglas)/Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 single crystal laminated composite under zero magnetic bias. The high-temperature pulse laser treatment could induce local crystallization along the laser scanning line, but adjacent domains remained still amorphous, which resulted in the thermal and lattice mismatch. Therefore, it could produce a residual stress between the crystalline and amorphous phases, which generated an internal bias field in the Metglas foil. The experimental results showed that the ME coefficient for the laser-treated laminate was enhanced to 1220 V/cm Oe at the resonance frequency of 23.32 kHz without a magnetic bias, which was two times higher than that of the untreated ME laminates. The induced ME voltage also showed a linear response to the applied AC magnetic field with an amplitude as low as 10−10 T at the resonance. The excellent ME performance could, therefore, serve as a promising and practicable application for highly sensitive magnetic field sensors under the zero bias field.

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.

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.

Nonvolatile eight-state memory prototype based on single-phase multiferroic hexaferrite at room temperature

Abstract Multiferroic materials exhibit both ferroelectricity and ferromagnetism, and their magnetoelectric effects can be modulated by both magnetic and electric fields. Thus, they exhibit great potential in next-generation data memory devices. In this study, we implemented an eight-state memory prototype based on room-temperature single-phase multiferroic Sr 3 Co 2 Fe 24 O 41 . Data were imported by a poling procedure with electric and magnetic fields and derived visa electric polarization, P m , or the magnetoelectric coefficient, α m . This memory prototype possesses the advantages of a single structure, being easy to integrate, having a high storage capacity and a high stability. In this research, we enriched the magnetoelectric coupling performance of multiferroic materials, which demonstrates their possibilities for applications in the memory field.

Effect of Structural Control on the Magnetoelectric Characteristics of Piezoelectric–Magnetostrictive Laminate Composite in Resonance and Off-Resonance Modes

In this study, it is reported that the magnetoelectric (ME) performance in the resonance mode and that in the off-resonance mode are reversed depending on the thickness fraction of the piezoelectric layer in a ME laminate composite composed of piezoelectric and magnetostrictive layers. The ME performance in the resonance mode increased as the thickness fraction of the piezoelectric layer was increased, while the ME performance in the off-resonance mode decreased. Based on the impedance spectrum analysis of fabricated ME laminate samples, it was confirmed that the thickness fraction of the piezoelectric layer had a significant influence on the mechanical loss of the device. The phase angle change and the mechanical quality factor at the anti-resonance frequency of the ME laminate were found to be useful for predicting the ME performance in the resonance mode. High aspect ratio of the laminate was favorable in both resonance and off-resonance modes.

Size-Dependent and Multi-Field Coupling Behavior of Layered Multiferroic Nanocomposites.

The prediction of magnetoelectric (ME) coupling in nano-scaled multiferroic composites is significant for nano-devices. In this paper, we propose a nonlinear multi-field coupling model for ME effect in layered multiferroic nanocomposites based on the surface stress model, strain gradient theory and nonlinear magneto-elastic-thermal coupling constitutive relation. With this novel model, the influence of external fields on strain gradient and flexoelectricity is discussed for the first time. Meanwhile, a comprehensive investigation on the influence of size-dependent parameters and multi-field conditions on ME performance is made. The numerical results show that ME coupling is remarkably size-dependent as the thickness of the composites reduces to nanoscale. Especially, the ME coefficient is enhanced by either surface effect or flexoelectricity. The strain gradient in composites at the nano-scale is significant and influenced by the external stimuli at different levels via the change in materials’ properties. More importantly, due to the nonlinear multi-field coupling behavior of ferromagnetic materials, appropriate compressive stress and temperature may improve the value of ME coefficient and reduce the required magnetic field. This paper provides a theoretical basis to analyze and evaluate multi-field coupling characteristics of nanostructure-based ME devices.

Electrospun poly(vinylidene fluoride-trifluoroethylene) based flexible magnetoelectric nanofibers

Flexible multiferroic nanofibers of poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) containing 20% w/w of bismuth ferrite doped with neodymium and cobalt (Nd0.05Bi0.95Fe0.95Co0.05O3) nanoparticles were fabricated by electrospinning. SEM micrographs show well aligned nanofibers with average diameter of 420 nm, X-Ray diffraction revealed R3c crystalline structure corresponding to Nd0.05Bi0.95Fe0.95Co0.05O3 and crystallinity β phase of PVDF-TrFE polymer. FTIR spectra and DSC thermogram were used to investigate the crystallization behavior of PVDF-TrFE and showed pure β phase crystals and high degree of crystallinity. Dielectric measurements determined a low conductivity was found (3 × 10−6–1 × 10−9 S) together with a piezoelectric coefficient of 35 pm/V (−d33) and low permittivity (εr = 30–42). Obtained nanofibers displayed a ferromagnetic hysteresis loop, with coercivity of 140 mT and remnant magnetization of 0.580 Am2/kg at room temperature. The coexistence of magnetic hysteresis and ferroelectric properties in Nd0.05Bi0.95Fe0.95Co0.05O3/PVDF-TrFE nanofibers indicates magnetoelectric performance and hint for potential applications on technological devices.

Magnetoelectric laminate composites: an overview of methods for improving the DC and low-frequency response

Magnetoelectric (ME) composite materials have a stronger ME coupling effect in resonant states than in non-resonant states. Typically, these resonant states appear at frequencies of several tens of kHz or even MHz. However, for DC and low-frequency applications of ME composites, obtaining a high ME response is critical. In recent years, many studies have attempted to improve the DC and low-frequency ME performance of ME composite materials at frequencies below 1 kHz. This article reviews the research and major progress in this field and investigates the application of other methods.

Piezoelectric and magnetoelectric behaviors of multifunctional cement-based laminated composites

One brand new cement-based magnetoelectric (ME) composite with its outstanding performance has initiated new directions for updated sensor development and monitoring applications in civil engineering. On the premise of applying the preferred processing method and laminated connectivity concluded before, the sandwich structured cement-based ME composites with different thickness ratios of the magnetostrictive layers to the piezoelectric layer have been developed to analyze the dominant influence factors on the key properties of the composites in this investigation. The contrastive results show that the piezoelectric factor and acoustic impedance of this laminated ME composite with the same type lead zirconate titanate (PZT) material present stable independence on the thickness ratios corresponding to the composition proportions. However, the important ME property of composites is strongly dependent on the applied field frequency, magnetic field Hdc and Hac, the PZT layer thickness and the relative field orientation. At 1 kHz, the maximum ME response αE31 of 1315 mV/cm·Oe for the ME composite with the intermediate PZT thickness of 0.8 mm was obtained. This strong ME response can be considered as the best ME performance ever found, which is superior to that of polymer-based composites reported. Moreover, it is worth to mention that the ME composites under different relative directions (vertical or parallel) of the magnetic field to the polarization orientation of PZT layer demonstrate greatly different ME coupling behaviors. Finally, it can be inferred the desirable properties of ME composites could be obtained by purposely choose the optimal volume fractions of different phases or other decisive parameters for accommodating various practical applications.

Diameter and sequence effects on magnetoelectric effect in FeCo/Pb(Zr,Ti)O3/Ni trilayered long cylindrical composite structures

Here we studied the magnetoelectric (ME) effect of FeCo/Pb(Zr,Ti)O3/Ni and Ni/Pb(Zr,Ti)O3/FeCo trilayered long cylindrical composites made up of negative magnetostrictive Ni layers, positive magnetostrictive FeCo layers and piezoelectric Pb(Zr,Ti)O3 (PZT) cylinders. Magnetostrictive layers were directly deposited on the PZT by electroless deposition. The bias magnetic field and the frequency dependences of ME effect were studied in both the axial and the vertical modes. The mean diameter of the trilayered long cylindrical composites has a strong impact on the ME effect. Keeping the height fixed, the resonant frequency and the maximum ME voltage coefficient decrease with the mean diameter of the cylinder increasing, while the optimal bias magnetic field HDC approximately remains constant. Besides, the ME effect is also influenced by the sequence of Ni and FeCo layers. The FeCo/Pb(Zr,Ti)O3/Ni cylinder obtains larger ME voltage coefficients, superior to those of the Ni/Pb(Zr,Ti)O3/FeCo in both modes. This work is significant for optimizing ME performance of the cylindrical layered ME composites in practical application such as magnetic field sensors and energy harvesters.

Effect of double layer thickness on magnetoelectric coupling in multiferroic BaTiO3-Bi0.95Gd0.05FeO3 multilayers

The effect of double-layer thickness and partial substitution of Bi3+ by Gd3+ is demonstrated for multiferroic BaTiO3–BiFeO3 2–2 heterostructures. Multilayers of 15 double layers of BaTiO3 and Bi0.95Gd0.05FeO3 were deposited onto (0 0 1) oriented SrTiO3 substrates by pulsed laser deposition with various double layer thicknesses. X-ray diffraction and high resolution transmission electron microscopy investigations revealed a systematic strain tuning with layer thickness via coherently strained interfaces. The multilayers show increasingly enhanced magnetoelectric coupling with reduced double layer thickness. The maximum magnetoelectric coupling coefficient was measured to be as high as 50.8 V cm−1 Oe−1 in 0 T DC bias magnetic field at room temperature, and 54.9 V cm−1 Oe−1 above 3 T for the sample with the thinnest double layer thickness of 22.5 nm. This enhancement is accompanied by progressively increasing perpendicular magnetic anisotropy and compressive out-of-plane strain. To understand the origin of the enhanced magnetoelectric coupling in such multilayers, the temperature and magnetic field dependency of is discussed. The magnetoelectric performance of the Gd3+ substituted samples is found to be slightly enhanced when compared to unsubstituted BaTiO3–BiFeO3 multilayers of comparable double-layer thickness.

Processing issues and their influence in the magnetoelectric performance of (K,Na)NbO3/CoFe2O4-based layered composites

Low temperature processing of environmentally-friendly (K,Na)NbO3- and CoFe2O4-based layered composites has been accomplished by hot pressing, and their electrical, piezoelectric and magnetoelectric properties have been characterized. High quality composite three-layer CoFe2O4/K0.5Na0.5NbO3/CoFe2O4 structures with defect-free interfaces were obtained by hot pressing at only 1000 °C, when highly reactive CoFe2O4 powders obtained by Pechini were used. Negligible chemical reactions at interfaces or interdiffusion across them took place during processing, while alkali volatilization was minimized. Dense, crack-free CoFe2−zGazO4/(K0.5Na0.5)1−xLixNb1−yTayO3/CoFe2−zGazO4 structures incorporating phases with enhanced piezoresponses have been also obtained, though in this case magnetoelectric coefficients were lower than expected. This is shown to be related with the presence of a core-shell type microstructure within the piezoelectric layer characteristic of (K0.5Na0.5)1−xLixNb1−yTayO3, which is stabilized by the low temperature processing. Procedures for further enhancement of the magnetoelectric response are proposed.

Theoretical design of high-performance polymer-based magnetoelectric of fibrilar structures

Low-dimensional magnetoelectric (ME) materials are attracting high attention both from the scientific and technological communities due to their interesting electrical, optical and mechanical properties allied to their novel applications in micro and nano smart-devices, drug delivery platforms, heterogeneous catalysis, tissue engineering, biosensors and bio-actuators, among others. Once the low dimensionality of these materials complicate the direct measurement of their performance at a large range of magnetic fields and high filler contents, this work theoretically evaluates low dimensional ME structures from spherical to ellipsoidal and fibre-shaped. The structures are based on CoFe2O4/poly(vinylidene fluoride) composites and the simulations are performed through the finite element method (FEM).Results for 50 wt percentage (wt.%) CoFe2O4 content samples reveal ME coefficients of 182 V/cm at 684 Oe for the spheres and 4241 V/cm at a magnetic field of 208 Oe on the medium eccentricity (of 1200) ellipsoidal structure. These fibre shaped ellipsoids exhibit higher ME values than the spheres and the axisymmetric fibres: 1601 V/cm at 30 Oe for an ellipsoid with eccentricity of 3200. Further, the fibrilar structure strongly decreases the ME performance and operational magnetic field to 14.7 V/cm at 1.38 Oe.These results establish the potential and limits, in terms of magnetic field and electric response, of the use of these composites and structures on technological ME device applications. Further, it demonstrates that suitable tuning of shape and dimensions allow to strongly increase ME response of the composites.