Magnetoelectric Effect In Composite Research Articles

Investigations of room temperature multiferroic and magneto-electric properties of (1-Φ) PZTFT-Φ CZFMO particulate composites

Multiferroic composites consisting of a single-phase multiferroic [0.6(PbZr0.53Ti0.47O3)-0.4(PbFe0.5Ta0.5)O3] as a matrix and a magnetostrictive phase (Co0.6Zn0.4Fe1.7Mn0.3O4) dispersed in the matrix are fabricated via hybrid synthesis technique. The structure and surface morphology studies using x-ray diffraction and field emission scanning electron microscopy techniques indicate the formation of 3-0 type particulate composites. Coexistence of soft-magnetic behavior and ferroelectric characteristics are confirmed for composites from magnetization vs magnetic field (M–H) and polarization vs electric field (P–E) measurements, respectively. Magneto-dielectric (MD) measurement shows significant changes in the dielectric properties with the application of a magnetic field, indicating the existence of strong MD behavior. The biquadratic nature of magneto-electric (ME) coupling is described by the Landau free energy equation arising from the strain transfer at the interfaces between the constituent phases. The direct magneto-electric voltage coefficient measurement also confirms very strong coupling between ferroelectricity and magnetism and supports the strain-mediated magneto-electric effect in composites. The Φ = 0.3 composite exhibits the maximum ME coefficient of 20.72 mV/cm Oe with MS = 24.62 emu/g, HC = 59.66 Oe, and piezoelectric coefficient value d33 = 19 pC/N. The strong magneto-electric effect along with low dielectric loss at room temperature in these composites suggests their suitability for multifunctional magneto-electric device applications such as magnetic sensors, etc.

Improvement of the magneto-electric effect of composites loaded with different magnetic particles for current sensor applications

This article proposes a methodology to improve the magneto-electric effect of a poly(vinylidene fluoride-co-trifluoroethylene) P(VDF-TrFe) copolymer, doped with nanoparticles of nickel (Ni) and nickel iron (NiFe). The preparation of the composite films were achieved through the solvent casting approach. First, P(VDF-TrFe) powders and (Ni and NiFe) nanoparticles are dispersed in dimethyl formamide (DMF) as a solvent to form a homogeneous solution. Then, the solution obtained is deposited on a flexible substrate by a spin coating process. After that, the NiFe doped composites are corona polarized, to improve the magneto-electric response of these composites. The purpose of this work is to investigate the influence of the magnetic charges added in the P(VDF-TrFe) copolymer, and to reveal the effect of corona charging (polarization) on the magneto-electric behavior of the used composites. The obtained results in this article show that both the doping and the electric polarization (piezo coefficient) significantly affect the generated alternating current during the application of an alternating magnetic field. However, the magneto-electric response of composites increases by doping and charging via corona poling effect and also by increasing the excitation frequency and the magnetic field amplitude. In addition, the magneto-electric responses of all composites after corona polarization were also discussed. This indicates that the magneto-electric coefficient and the current can be increased with polarized composites. A good response is observed for P(VDF-TrFe) + 3% Ni with a piezoelectric coefficient d33 = 21.2 (pC/N)

Magnetoelectric properties in bulk and layered composites

Purpose – The purpose of the paper was to present a comparative study on the microstructure and magnetoelectric effect of new magnetoelectric composites based on TbFe2 compound and Ni0.3Zn0.62Cu0.08Fe2O4, CoFe2O4 ferrites as a magnetostrictive phase, Pb(Fe1/2Ta1/2)O3 (PFT), Pb(Fe1/2Nb1/2)O3 relaxors as a ferroelectric phase and polyvinylidene fluoride (PVDF) as piezoelectric phase. Design/methodology/approach – The ceramic components of composites were prepared by the standard solid-state reaction method. The intermetallic compound TbFe2 was prepared with an arc melting system with a contact-less ignition in a high purity argon atmosphere. The metal – ceramic – polymer composites were prepared in a container in which powder of PVDF were dissolved in N,N-dimethylformamide with continuous mixing and at the controlled temperature. Ceramic composites were prepared as bulk samples and multilayer tape cast and co-sintered laminates. The microstructure of the composites was investigated using scanning electron microscopy (SEM). The magnetoelectric effect of the composites was evaluated at room temperature by means of the dynamic lock-in method. Findings – SEM analysis revealed a dense, fine-grained microstructure and uniform distribution of the metallic, ferrite and relaxor grains in the bulk composites. The SEM image for multilayer composite illustrates the lack of cracks or delaminations at the phase boundaries between the well-sintered ferrite and relaxor layers. For all studied composites, the magnetoelectric coefficients at a lower magnetic field increase, reaches a maximum and then decreases. Originality/value – The progress in electronic technology is directly linked to advances made in materials science. Exploring and characterizing new materials with interesting magnetoelectric properties, in the rapidly growing field of functional materials, is an important task. The paper reports on processing, microstructure and magnetoelectric properties of novel magnetoelectric composites.

Synthesis and magnetoelectric effect of composites with CoFe2O4-epoxy embedded in 3–1 type porous PZT ceramics

Three-phase magnetoelectric (ME) composites of lead zirconate titanate (PZT)/cobalt ferrite CoFe2O4 (CFO)/epoxy were synthesized in sequence by a tert-butyl alcohol (TBA)-based freeze-casting technique, a chemical solution deposition method, and an impregnation process. The novel pseudo 3–0–1 type composite structure with a high content of CFO was examined using SEM and XRD. The composites showed not only stable and excellent dielectric behavior in a wide frequency range, but also good ferroelectricity and ferromagneticity at the same time, as can be seen from the typical electrical and magnetic hysteresis loops. The ME effect of the resultant 3–0–1 type ferroelectric/ferromagnet/polymer composites was found to be significantly dependent on the content of PZT and CFO. The maximum ME coefficient of 2.2mV/cmOe was observed when the PZT volume fraction is 0.5 and CFO mass fraction is 0.2. This synthesis route we proposed provides a new connectivity type of ME composite and shows potential applications in sensors and transducers.

Magnetoelectric Properties of Two-Layered Composites Tb0.12Dy0.2Fe0.68 – PbZr0.53Ti0.47O3

At frequencies of the measuring magnetic field of 9.9–253 kHz over a temperature range from 79 K to 289 K the magnetoelectric effect in two-layered ferromagnetic-piezoelectric composites Tb0.12Dy0.2Fe0.68 – PbZr0.53Ti0.47O3 with ferromagnetic Tb0.12Dy0.2Fe0.68 and piezoelectric PbZr0.53Ti0.47O3 layers of 6 × 6 × А mm3 (A = 0.6, 0.9, and 1.2) and 8 × 6 × 0.3 mm3 in size, respectively, has experimentally been studied. Resonant frequencies of bending and longitudinal oscillations of composite samples of Tb0.12Dy0.2Fe0.68 – PbZr0.53Ti0.47O3 have been calculated. We have studied dependences of the magnetoelectric effect in composites on a frequency of the measuring magnetic field, a thickness of a Tb0.12Dy0.2Fe0.68 layer, the bias magnetic field strength, and temperature.

Magnetoelectric effect in composites of magnet, metal-cap, and piezoceramic

We report on the magnetoelectric (ME) effect in three-phase magnet-metal-cap-piezoceramic composites of a thickness-polarized Pb(Zr,Ti)O3 disk bonded between two truncated conical brass caps and two thickness-magnetized NdFeB magnets along the thickness direction. The effect originated from the product of the magnetic attractive–repellent effect in the magnets and the amplified piezoelectric effect in the cap-disk assembly. The composites exhibited a ME voltage coefficient αV of ∼2.6 mV/Oe in the non-resonance frequency range of 0.1–10 kHz with good voltage-field linearity in the field range of 10-3–10 Oe, besides an enhanced αV of 167.4 mV/Oe at a resonance frequency of 14.4 kHz. Compared to conventional two-phase and three-phase magnetostrictive material-contained ME composites, these composites possessed two distinct benefits of higher property-tailorable flexibility and requiring no external dc bias magnetic field to enable an obvious αV.

Giant magnetoelectric effect in composite materials in the region of electromechanical resonance

The magnetoelectric effect in multilayer ferrite-piezoelectric composites has been theoretically and experimentally studied. Using the method of effective parameters, an expression for the magnetoelectric coefficient is determined and its frequency dependence is analyzed. It is shown that, in the region of electromechanical resonance, the magnitude of the effect exceeds a low-frequency value by more than an order of magnitude. The results of calculations obtained for a nickel ferrite spinel-PZT composite are in good agreement with the experimental data.

Magnetoelectric effect in composites of piezoelectric and piezomagnetic phases.

The magnetoelectric effect in composites of piezoelectric and piezomagnetic phases is investigated theoretically. The magnetoelectric effect is totally absent in these two constituent phases, and so it is a new property of the composites. A generalized theoretical framework based on a Green's function method and perturbation theory is proposed to treat the coupled magnetoelectric behavior in the composites. Explicit relations for determining the effective magnetoelectric effect in the composites are derived, and the different approximate expressions for the magnetoelectric coefficient of the fibrous composites with 1-3 or 3-1 connectivity of phases are given. To illustrate the technique, numerical calculations of the magnetoelectric coefficients of the BaTiO3-CoFe2O4 composites for various phase compositions and particle shapes are performed. The theoretical estimates are shown to be in agreement with available experimental results, and also show the interesting magnetoelectric behavior of the composites.

The magnetoelectric effect of composites and polycrystals

Abstract The effective (linear) magnetoelectric coefficient of a composite made of two isotropic materials can be determined exactly, if the properties of the pure components, the effective dielectric constant, and the magnetic permeability of the composite are known. No further knowledge is required of the relative fractions of the components, or of the exact microstructure of the composite. For an isotropic composite there exists a relation that may be put in a symmetric, determinant from