Converse Magnetoelectric Coefficient Research Articles

Large converse magnetoelectric effect in Metglas FeCoBSi and 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 laminated composite

Converse magnetoelectric (CME) effect is investigated in a FeCoBSi/0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 laminated composite by using induction method within different frequencies. A large CME coefficient of 3.05 G/V is observed at the resonance frequency of 76.5 kHz under a low bias magnetic field of 50 Oe. The CME coefficient of the heterostructure is almost constant and exhibits a relatively high value in a wide frequency span of 1–64 kHz. The origin of large CME effect and the advantages of Metglas acting as ferromagnetic layer are discussed in the present paper.

Effect of phase transformation on the converse magnetoelectric properties of a heterostructure of Ni49.2Mn29.6Ga21.2 and 0.7PbMg1/3Nb2/3O3-0.3PbTiO3 crystals

We report experimentally and theoretically the effect of phase transformation on the converse magnetoelectric (CME) properties of a heterostructure formed by one layer of piezoelectric 0.7PbMg1/3Nb2/3O3-0.3PbTiO3 (PMN-PT) crystal sandwiched between two layers of ferromagnetic shape memory Ni49.2Mn29.6Ga21.2 (Ni–Mn–Ga) crystal. The CME coefficient (αB) of the heterostructure remains minimally and relatively constant in the martensitic phase (<28 °C), attains its maximum value in the martensitic-austenitic phase transformation (28–39 °C), and decreases gradually with increasing temperature in the austenitic phase (>39 °C). Giant resonance αB of 18.6 G/V is found at 32 °C under a very low bias magnetic field of 150 Oe.

Comparison of Effective Direct and Converse Magnetoelectric Effects in Laminate Composites

A theoretical analysis is used to prove that a piezoelectric/magnetostrictive laminate composite has equivalent effective direct and converse magnetoelectric (ME) coefficients. Experimentally a PZT/Terfenol-D/PZT trilayer laminate composite was fabricated and both direct and converse ME coefficients were characterized by measuring the magnetic-field-induced polarization and electric-field-induced magnetization. The laminate sample exhibits similar DC magnetic bias dependence and resonance response for both direct and converse ME effects. The magnitudes of effective ME coefficients are of the same order but significantly different and both are smaller than theoretical prediction. This raises the question as to whether these coefficients are equivalent in a layered composite or to the accuracy of ME coefficient data measurement.

Influence of electric voltage bias on converse magnetoelectric coefficient in piezofiber/Metglas bilayer laminate composites

Experimental data on a piezofiber/Metglas bilayer composite subjected to both a dc electric voltage bias and a dc magnetic field bias while exciting it with an ac electric driving voltage are presented. As reported in previous studies, a dc magnetic field bias exists to maximize the converse magnetoelectric coefficient. Experimental data show that the optimum dc magnetic field bias is a function of applied dc electric voltage. Furthermore, it is revealed that an optimum dc electric voltage bias exists to further maximize the converse magnetoelectric coefficient.

Resonance converse magnetoelectric effect in a dual-mode bilayered composite of Pb(Mg 1/3Nb 2/3)O 3–PbTiO 3 and Tb 0.3Dy 0.7Fe 1.92

We report the resonance converse magnetoelectric (CME) effect in a bilayered composite with two different resonance modes. The composite consists of a thickness-polarized piezoelectric 0.7Pb(Mg 1/3Nb 2/3)O 3–0.3PbTiO 3 (PMN–PT) crystal plate and a length-magnetized magnetostrictive Tb 0.3Dy 0.7Fe 1.92 (Terfenol-D) alloy plate. A low-frequency bending mode resonance is observed in the composite in addition to a high-frequency longitudinal mode resonance. The bending and longitudinal mode resonances are found at 17.5 and 66.5 kHz, respectively, while their respective resonance CME coefficients are as large as 4.1 and 7.9 G/V, at an optimal bias magnetic field of 400 Oe. This dual-mode resonance CME effect forms a basis for dual-mode/-frequency operations of coil-free electromagnetic devices.

Giant sharp converse magnetoelectric effect from the combination of a piezoelectric transformer with a piezoelectric/magnetostrictive laminated composite

Giant sharp converse magnetoelectric (CME) coefficient of 11.9G∕V is obtained in a heterostructure formed by combining a Rosen-type 0.7Pb(Mg1∕3Nb2∕3)O3–0.3PbTiO3 (PMN-PT) piezoelectric single-crystal transformer with a CME laminated composite of a length-magnetized Tb0.3Dy0.7Fe1.92 (Terfenol-D) magnetostrictive alloy plate sandwiched between two thickness-polarized, electroparallel-connected PMN-PT piezoelectric single-crystal plates. The observed giant sharp CME is found to originate from the step-up voltage-gain effect in the transformer and the resonance CME effect in the laminated composite. This heterostructure has promising applications in electrically controlled magnetic memory devices.

Magnetoelectric and converse magnetoelectric responses in Tb x Dy1−xFe2−y alloy & Pb(Mg1/3Nb2/3)(1−x)TixO3 crystal laminated composites

Measured results of magnetoelectric (ME) and converse magnetoelectric (CME) effects of TbxDy1−xFe2−y/Pb(Mg1/3Nb2/3)(1−x)TixO3/TbxDy1−xFe2−y (TD/PMNT/TD) and PMNT/TD/PMNT laminated composites are presented. ME effect was determined by measuring laminate voltage output under a Helmholtz-generated AC field biased by a DC field (0–1 kOe) (1 Oe = 79.58 A/m). The CME effect was measured by recording the voltage induced in a solenoid encompassing the ME sample while exposed to a DC bias field and PMNT layer driven by a 10 V AC source. The ME and CME responses in the two laminated structure are linear. The highest values of ME coefficients in TD/PMNT/TD and PMNT/TD/PMNT composites are 384 mV/Oe and 158 mV/Oe, respectively, while the highest values of CME coefficients in the two composites are 118 mG/V and 162 mG/V (1 G=10−4 T), respectively.

Converse magnetoelectric effects in piezoelectric–piezomagnetic layered composites

By using the product effect of converse piezoelectric effect and piezomagnetic effect, a multilayer piezoelectric–piezomagnetic composite consisting of transversely poled piezoelectric Pb(Mg 1/3Nb 2/3)O 3–PbTiO 3 crystal layers and longitudinally magnetized magnetostrictive Tb 0.27Dy 0.73Fe 2 layers has been developed and its converse magnetoelectric (ME) effect has been studied. A wide bandwidth of the frequency peak under different magnetic bias fields was also observed. The largest value of converse ME coefficient α B at a resonance frequency of 78.6 kHz is 1.15 G/V, which is ∼10 times higher than the value at sub resonant frequencies. This composite exhibits a promising potential in the magnetic force devices electrically controlled.

Direct and converse magnetoelectic effect in laminate bonded Terfenol-D–PZT composites

Results from measurements of the direct and converse magnetoelectric (ME) effect on a three-layer, epoxy-bonded, laminate composite are presented. The laminae are a single transversely polarized piezoelectric elements (PZ29) sandwiched between two longitudinal-magnetically polarized magnetostrictive TD elements (Terfenol-D—TX GMM). The direct ME effect was determined by measuring laminate output with a Helmholtz-generated AC field (up to 7 Oe) in the range 50 Hz–100 kHz biased by a DC field (0–1000 Oe). Peak voltage output occurred at the sample's mechanical resonant frequency, its value depending on the strength and direction of the applied magnetic field. The peak output was 3061 mV at 3 Oe AC field and 1000 Oe bias, equivalent to 74.4 V cm −1 Oe −1. The peak output coefficient, however, was 93.6 V cm −1 Oe −1 at 0.1 Oe AC field and 1000 Oe DC bias. The reduction at higher drive amplitudes was attributed to increased Young's modulus of the TD phase. Anomalous peaks in the low frequency spectrum of sample's output are explained. The converse magnetoelectric effect was measured by recording the voltage induced in a solenoid encompassing the ME while exposed to a DC bias field and the PZ phase driven by a 10 V AC source. The peak output is shown to depend on the strength of the applied DC magnetic field and developed a maximum field of 15.4 Oe at the sample's mechanical resonant frequency. This equates to a converse magnetoelectric coefficient of 55 Oe cm kV −1.

Converse magnetoelectric effect in three-phase composites of piezoceramic, metal cap, and magnet

We report experimentally and theoretically the converse magnetoelectric (CME) effect in a three-phase piezoceramic-metal-cap-magnet composite made by sandwiching a thickness-polarized Pb(ZrxTi1−x)O3 (PZT) disk between two truncated conical brass caps and two thickness-magnetized SmCo disks. The reported CME effect originates from the product of the converse piezoelectric effect in the PZT disk, the mechanical transformation/amplification effect in the brass caps, and the magnetic induction effect in the SmCo disks. The composite exhibits a large CME coefficient (αB) in excess of 2mG∕V with a flat response in the broad frequency range of 0.1–100kHz. The measured magnetic flux density shows an extremely linear relationship to the applied voltage with amplitude varying from 10to100V over a wide range of detection distance of 0.7–6.5mm. This electromechanomagnetically coupled effect enables applications of the composite in coil-free magnetic flux control devices, featuring smaller Joule heating loss, wider operational bandwidth, and greater property-tailorable flexibility compared to conventional electromagnet-based devices.

Converse magnetoelectric effect in laminated composites of PMN–PT single crystal and Terfenol-D alloy

We have found experimentally and theoretically that laminated composites comprising one layer of length-magnetized Tb0.3Dy0.7Fe1.92 (Terfenol-D) magnetostrictive alloy sandwiched between two layers of thickness-polarized, electro-parallel-connected 0.7Pb(Mg1∕3Nb2∕3)O3–0.3PbTiO3 (PMN–PT) piezoelectric single crystal have a large converse magnetoelectric effect characterized by a large magnetic induction in response to an applied ac voltage. The reported converse magnetoelectric effect originates from the product of the converse piezoelectric effect in the PMN–PT layers and the converse magnetostrictive effect in the Terfenol-D layer. Large converse magnetoelectric coefficient in excess of 105mG∕V is obtained in the composites at a low magnetic bias field of 170Oe. The measured magnetic induction has an excellent linear relationship to the applied ac voltage with amplitude varying from 50to160V. These made the composites to be a promising material for direct realization of core-free magnetic flux control devices.