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Acoustically actuated magnetoelectric (ME) antennas based on resonant magnetoelectric coupling within ferromagnetic/piezoelectric ME laminated composites have recently been considered as a promising solution for antenna miniaturization. However, its radiation performance has been theoretically overestimated, since the negative effects on performances due to the magnetization saturation and the nonlinear mechanical behavior that occur from high-field driving have not been paid enough attention. This work presents a unique equivalent-circuit-based numerical method to analyze the near-field resonance radiation performances of ME antennas driven by high electric fields. In this method, we establish an equivalent circuit of the converse magnetoelectric effect for a ME laminated composite to describe the operating principle of acoustically actuated electromagnetic radiation. The equivalent parameters related to resonance characteristics are determined by fitting the circuit model to the data from frequency response measurements of the near-field magnetic flux density. The validity of the model is verified by comparing the theoretical predictions with the experimental results, in the view of the volume fraction dependence of the mechanical resonance-related radiation characteristics of the fabricated ME composites. Based on the proposed model, the influence of driving voltage amplitude on near-field radiation performances is further analyzed by experimental fitting to the model, and the potential limiting factors of ME antennas are discussed according to the driving-amplitude dependence of parameters obtained from the fit. This work provides an effective and engineering-friendly approach to predict the evolution of ME antenna performances, leading a way to improve the performance limit for resonant magnetoelectric coupling. [ABSTRACT FROM AUTHOR]

Long-wave radio station based on an electrically small antenna and mechanical transmitter based on a rotating permanent antenna are commonly used for super low frequency (SLF, 30–300 Hz) communication. The current challenge is the difficulty in developing both an efficient and a miniaturized SLF transmitter. Enlightened by the advantages of piezoelectric motor over conventional electromagnetic motor in terms of efficiency and the output torque in low frequency band, we propose a piezoelectrically driven magnetic pendulum transmitter by combining a magneto-mechano-electric (MME) cantilever and a swinging magnet in this work. The magnetic force coupling between the MME cantilever and the swinging magnet is optimized by changing the thickness and the attached position of the used Metglas laminates. The experimental results show that the piezoelectrically driven magnetic pendulum transmitter has a working frequency of 57 Hz, and a flux density of 149 f Tpk at 100 m distance could be expected with a low power consumption of 40.64 mW. When driving the same magnet with an electromagnetic motor, however, the required power consumption reaches 4.2 W for 57 Hz magnetic field radiation. By dividing the induced magnetic moment over the consumed power, the effective radiation efficiency of our proposed piezoelectrically driven SLF magnetic pendulum transmitter significantly increased from 0.55 to 17.4. This proof-of-concept work is believed to open a dimension for the design and the application of efficient SLF mechanical transmitter in the future. [ABSTRACT FROM AUTHOR]

Traditional piezoelectric adaptive lenses (ALENS) are fabricated by piezoceramics with transparent liquids as the filling media. However, it is challenging to achieve high focal sensitivity and long-time robustness because of the low piezoelectricity of ceramics as well as the evaporation and leakage of the liquids. To overcome the above-mentioned issues, we design a piezoelectric lens based on a radial extension-arching mode by using polydimethylsiloxane films and Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIMNT) relaxor ferroelectric single crystals to replace the transparent liquids and Pb(Zr, Ti)O3 (PZT) ceramics, respectively. Due to the ultrahigh piezoelectric properties (d33 ∼ 1500 pC N−1 and d31 ∼ 730 pC N−1) of the PIMNT crystals and the optimized radial extension-arching structure, an ultrahigh focal sensitivity (8.5 cm V−1 and a fast response time (∼102μs) is achieved, outperforming conventional ALENS based on piezoceramic actuators (∼103 μs and ∼10−1 cm V−1) and dielectric elastomer actuators (∼105 μs and ∼10−2 cm V−1). The largest output displacement of our designed ALENS is up to 53.6 μm at 4.2 kHz under 80 Vpp, and its focus is in the range of 57.44 cm to ∞. Furthermore, its performance remains unchanged after 4 × 107 vibration cycles, indicating its long-time robustness. This work sheds light on the design of advanced adaptive optical systems, where an ultrahigh focal sensitivity and a fast response are required. [ABSTRACT FROM AUTHOR]

In this work, we report an enhanced magneto-mechano-electric (MME) coupling in Ni/Pb(Zr,Ti)O3 (PZT) ceramic composited ladder-type cantilever attached with a tip mass of NdFeB magnet, which simultaneously exhibits the magnetic flux concentration effect and the stress concentration effect, and therefore, it shows an enhanced extremely weak-field (EWF) coupling ability. Investigations show that the proposed MME energy harvester (EH) can generate an output power density of 7.16 μW Hz−1 Oe−2 cm−3, which is the highest value compared to the state of the art MME energy harvesters. Under an EWF of even as low as Hac = 0.1 Oe (about half level of the geomagnetic field), the proposed MME-EH can still produce a peak–peak output power of 23.5 μW, which is enough power to light up 4 LEDs in real time. Furthermore, it can drive a wireless sensor communication system in real time under a weak Hac = 0.75 Oe excitation, demonstrating it has potential to serve as a micro-energy source of wireless sensor networks in EWF circumstance. This work is not only beneficial but has also inspired future multi-function-integrated material and smart electronic device designs in Internet of Things in EWF circumstance. [ABSTRACT FROM AUTHOR]

In this work, we report a cofired-12-layer ceramic based standing-wave linear piezoelectric ultrasonic micromotor (SW-LPUM) with a high-load-density using LiCO3 doped 0.05Pb(Mn1/3Sb2/3)O3-0.47PbZrO3-0.48PbTiO3 (PMnS-PZT) material. The proposed SW-LPUM features a miniaturized structure (12.45 × 5.3 × 3.5 mm3) and excellent comprehensive actuation performances, such as fast response time (0.05 ms), high resolution (50 nm), and broad adjustable velocity range (from 0.01 to 123.7 mm s−1). Specifically, its high load density (11.0 mN mm−3) under a single-phase voltage drive is higher than that of most reported LPUMs. The elaborate multilayer structure based on hard-type PMnS-PZT ceramic enables the micromotor to continuously operate without obvious temperature rise, showing its practical value for high-precision positioning. [ABSTRACT FROM AUTHOR]

Low driving voltage is important for miniaturization and untethered service of millirobots made of piezoelectric materials. In this research, we designed a bio-inspired bimorph-structured millirobot with a transparent relaxor ferroelectric crystal. Due to the ultrahigh piezoelectricity of the relaxor ferroelectric crystals and the optimized bimorph-based structure, the millirobot shows a maximum moving speed up to 9.22 b s−1 (body length per second) at 100 V, while the minimum driving voltage for initial movement can be as low as 3 V, which is more than two orders of magnitude smaller than that of millirobot based on dielectric elastomers. The maximum and minimum power consumptions of the millirobot are 71.6 mW and 85.9 μW, respectively. The robustness of the millirobot is reflected in its mechanical load stability carrying a 78 g mass (97.5 times of its weight) and its cryogenic tolerance. This work is believed to be beneficial to the design of various robust electromechanical devices with low driving voltage. [ABSTRACT FROM AUTHOR]

Multiferroic magnetoelectric (ME) composites have been continually attracting researchers' attention because of the significant potential for building functional devices. Unlike conventional ME devices under quasi-static or low-power excitation, e.g., sensors, energy harvesters, and random memories, high-power ME devices like recently proposed ME antennas will perform complex dynamic behavior. The voltage-driven nonlinearity in 1–1-typed ME resonators was reported from the perspective of frequency-response curve in our last work. Here, we described both theoretically and experimentally a previously unobserved jumping and hysteresis effect in its magnetic bias characteristic. A direct link between the bias-response and the frequency-response characteristics was also experimentally provided to analyze the origin of the nonlinear behavior in the bias-response curve. In addition, the cubic spring constant k3 was theoretically calculated and compared to qualitatively explain the difference of our obtained threshold voltage that generated the first and second jumping resonances in the dual-peak bias-response curve. In contrast to our previous research, this work reveals the loading direction of the applied magnetic bias field, which plays a significant role when we consider the selection of an optimized bias field for high-power ME devices. Moreover, the sharp jumping in the bias-response curve is also a potential for opening dimensions for ME community. [ABSTRACT FROM AUTHOR]

In this work, we theoretically and experimentally report a NdFeB magnet/piezoelectric composite cantilever with varying stiffness for enhancing magneto-mechano-electric (MME) coupling under weak AC magnetic field Hac excitation. Measurement results show that the MME composite cantilever can produce a relatively high peak-peak output power of 12.8 mW and a peak-peak current of 0.735 mApp under Hac = 7 Oe at a resonance frequency of 36 Hz. Even when Hac is as low as 0.2 Oe, equivalent to the level of the earth magnetic field, it can still drive 4 LED lighting. The obtained results are obviously superior to previous reports, confirming the MME cantilever harvester has potential to harvest the stray magnetic field energy from electrical power cables for continuously powering wireless sensor networks. [ABSTRACT FROM AUTHOR]

In this study, we report an enhanced electrical manipulation of magnetic susceptibility in ferromagnetic amorphous alloy ribbon using a piezoelectric bimorph actuator. Theoretically, the strain produced by the piezoelectric bimorph and then coupled into the amorphous alloy ribbon is larger than that of a single piezoelectric plate under an identical applied electric field, thus resulting in a stronger magnetoelectric (ME) coupling for electrically manipulating magnetic susceptibility. Our experimental results have shown that the initial susceptibility tunability of the amorphous alloy ribbon upon the tuning electric field applied on the piezoelectric bimorph ranging from 0 kV/cm to 5 kV/cm can reach up to 750% at low-frequency of 1 kHz and maintain 80% at 1 MHz. This study expands the structure design of ME smart devices, especially the electrically controllable magnetic devices. [ABSTRACT FROM AUTHOR]

(0.98-x)Bi(Sc3/4In1/4)O3-xPbTiO3-0.02Pb(Zn1/3Nb2/3)O3 (BSI-PT-PZN) high temperature piezoelectric ceramics were prepared by traditional solid-state reaction method. Combining X-ray diffraction results with piezoelectric data, it was found that the morphotropic phase boundary (MPB) occurred at x = 0.575. The piezoelectric constant d33, curie temperature Tc, and electromechanical coupling factor kp of BIS-PT-PZN ceramics with MPB composition were 427 pC/N, 412 °C, and 0.51, respectively. Furthermore, the strain of BIS-PT-PZN ceramics reached up to 0.25% under the electric field of 40 kV/cm. Temperature-dependent electromechanical coupling coefficient for MPB composition was stable from room temperature up to 350 °C. The piezoelectric properties of BIS-PT-PZN ceramics were comparable to that of 0.36BiScO3-0.64PbTiO3 (BS-PT) ceramics, and the piezoelectric constant d33 of BIS-PT-PZN ceramics was about twice that of our previous reported 0.4Bi(Sc3/4In1/4)O3-0.6PbTiO3 (BSI-PT) ceramics. The reduction in the expensive Sc2O3 content and comparable piezoelectric properties with BS-PT ceramics indicated that BIS-PT-PZN ceramics were promising for commercial applications as high temperature actuators and sensors. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramic (1 - x)Bi(Sc3/4In1/4)O3-xPbTiO3 (BSIPT) (0.45 ≤ x ≤ 0.70) solid solutions near the morphotropic phase boundary (MPB) were developed for high temperature piezoelectric transducer and actuator applications. It was found that the MPB composition of BSIPT ceramics was in the vicinity of x = 0.6, where it had relatively small tolerance factor t = 0.901 resulting in a high TC of 457 °C, and also optimal properties such as the high Pr = 25.4 μC/cm2, &eh;r = 1153, d33 = 201 pC/N, kp = 0.34, and the low Ec = 23.5 kV/cm. Measurements also showed that the depoling temperature was 360 °C, about 200 °C higher than that of commercialized PZT ceramics, which indicated good temperature stability. BSIPT ceramics are promising candidates for high temperature applications. [ABSTRACT FROM AUTHOR]

In previous theoretical analyses, magnetoelectric (ME) coupling coefficient αME of piezoelectric/piezomagnetic laminates for static and dynamic modes is usually regarded as one that is not related to laminates' sizes (length and width). In micrometer or sub-millimeter ME laminates, the decrease in ME coupling was normally attributed to the substrate's clamping effect. Here, we report an effective ME coefficient αME,eff including sizes' effect based on magnetic circuit method including the size induced demagnetization effect, which predicted that as sizes of ME laminates decrease from 100 mm to 10-3 mm, αME,eff will dramatically decreases from ∼5 V/cm-Oe to 0.08 V/cm-Oe. Size decrease in ME laminates will result in a decrease in effective magnetic induction Bμ inside piezomagnetic phase in an applied magnetic field H. Our analyses further disclose a degenerate mode occurred between the longitudinal and transverse resonance modes, which may cause a weakened ME coupling. Finally, our analyses indicate that a thin and long ME laminate will exhibit a stronger ME coupling, which was then confirmed by our experimental results. [ABSTRACT FROM AUTHOR]

Multiferroic magnetoelectric materials, which simultaneously exhibit ferroelectricity and ferromagnetism, have recently stimulated a sharply increasing number of research activities for their scientific interest and significant technological promise in the novel multifunctional devices. Natural multiferroic single-phase compounds are rare, and their magnetoelectric responses are either relatively weak or occurs at temperatures too low for practical applications. In contrast, multiferroic composites, which incorporate both ferroelectric and ferri-/ferromagnetic phases, typically yield giant magnetoelectric coupling response above room temperature, which makes them ready for technological applications. This review of mostly recent activities begins with a brief summary of the historical perspective of the multiferroic magnetoelectric composites since its appearance in 1972. In such composites the magnetoelectric effect is generated as a product property of a magnetostrictive and a piezoelectric substance. An electric polarization is induced by a weak ac magnetic field oscillating in the presence of a dc bias field, and/or a magnetization polarization appears upon applying an electric field. So far, three kinds of bulk magnetoelectric composites have been investigated in experimental and theoretical, i.e., composites of (a) ferrite and piezoelectric ceramics (e.g., lead zirconate titanate), (b) magnetic metals/alloys (e.g., Terfenol-D and Metglas) and piezoelectric ceramics, and (c) Terfenol-D and piezoelectric ceramics and polymer. The elastic coupling interaction between the magnetostrictive phase and piezoelectric phase leads to giant magnetoelectric response of these magnetoelectric composites. For example, a Metglas/lead zirconate titanate fiber laminate has been found to exhibit the highest magnetoelectric coefficient, and in the vicinity of resonance, its magnetoelectric voltage coefficient as high as 102 V/cm Oe orders has been achieved, which exceeds the magnetoelectric response of single-phase compounds by many orders of magnitude. Of interest, motivated by on-chip integration in microelectronic devices, nanostructured composites of ferroelectric and magnetic oxides have recently been deposited in a film-on substrate geometry. The coupling interaction between nanosized ferroelectric and magnetic oxides is also responsible for the magnetoelectric effect in the nanostructures as was the case in those bulk composites. The availability of high-quality nanostructured composites makes it easier to tailor their properties through epitaxial strain, atomic-level engineering of chemistry, and interfacial coupling. In this review, we discuss these bulk and nanostructured magnetoelectric composites both in experimental and theoretical. From application viewpoint, microwave devices, sensors, transducers, and heterogeneous read/write devices are among the suggested technical implementations of the magnetoelectric composites. The review concludes with an outlook on the exciting future possibilities and scientific challenges in the field of multiferroic magnetoelectric composites. [ABSTRACT FROM AUTHOR]

A magnetoelectric composite consisting of a multilayer Pb(Zr,Ti)O3 piezoelectric (d33) stack and a magnetostrictive (Galfenol and/or Terfenol-D) rod assembled in a prestressed frame in a longitudinal-longitudinal configuration has been found to have a high magnetoelectric (ME) charge coupling to an applied magnetic field. Values of the ME charge coefficient as high as 16.4 nC/Oe (or 3.6×10-6 C/m2 Oe) were found at quasistatic frequencies and 123 nC/Oe (or 2.8×10-5 C/m2 Oe) under resonance drive, which are 100–1000 times higher than that previously reported for other ME laminates. [ABSTRACT FROM AUTHOR]

Three-phase magnetoelectric (ME) laminate composites made of high-permeability (μ) MnZnFe2O4, magnetostrictive Tb1-xDyxFe2-y, and piezoelectric Pb(Zr,Ti)O3 layers and operated in longitudinal magnetization and transverse polarization (L-T) bending modes have been studied. High-μ MnZnFe2O4 layers act as flux concentrators. This results in increased apparent piezomagnetic coefficients in the magnetostrictive Tb1-xDyxFe2-y layer and consequently larger induced voltages across the piezoelectric Pb(Zr,Ti)O3 layers. We find the enhanced ME field coefficients of up to 8 times for longitudinal magnetization mode, and up to 28 times for transverse magnetization mode, under small dc magnetic field bias. [ABSTRACT FROM AUTHOR]

Tremendous progress has been made in boosting the realization of magnetoelectric (ME) magnetometers based on the direct ME effect (DME) for bulk ME laminates. In this work, we studied the potential of an electrically driven bulk magnetic field sensor based on the converse ME effect (CME). Starting from a discussion about the dependence of the induced voltage from the pickup coil on coil parameters and the CME coupling process, we then experimentally measured the optimized bias field in the off resonance region and observed the double-peak phenomenon that occurred within the resonance window. More importantly, the optimization with respect to the sample's dimension, excitation voltage, and frequency was conducted to improve the sensing capability for low-frequency magnetic fields. It was experimentally found that a limit of detection (LoD) of ∼115 pT for a magnetic field of 10 Hz and ∼300 pT for a magnetic field of 1 Hz was achieved when exciting the ME laminate at 1 V without any bias field. In this case, the power consumption for the ME laminate is only 0.56 mW, which is much lower compared to tens of milliwatts (10–100 mW) for optically pumped or flux gate sensors (excluding the power consumption from the electronics) and also shows advantages over conventional ME magnetic field sensors based on DME with a current pump. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

It is an important scientific and engineering challenge to sense a weak magnetic field HAC at extremely low-frequency (LF) below 1 Hz due to the large LF noise. In this work, we presented an amplitude modulation method (AMM) for quasi-static magnetic field detection based on a magnetoelectric (ME) sensor and a lock-in amplifier. Different from previously reported frequency conversion technology, the weak LF magnetic signal is demodulated directly from the output response of a ME sensor driven at its resonance frequency. Experimental results demonstrated that the absolute resolution with respect to a 100 mHz HAC is as low as 100 pT, indicating an enhancement by a factor of 50% in comparison with previous reports. This proposed AMM should pave another route for LF weak HAC detection. [ABSTRACT FROM AUTHOR]

Space exploration requires reliable measurements of space-radiation induced charge or its electric potential in a wide range in a satellite. Here, we report one pair of 3D printed soft multilayer differential capacitors, which are piezoelectrically actuated in vibration to convert the input static DC charge (high electric potential) into a measurable small dynamic AC output signal through charging and discharging between two differential capacitors. The fabricated prototype features linear responses to a high potential change and also high reliability. Moreover, the method proposed in this work is promising to achieve rapid manufacturing of functional devices in batch processing. [ABSTRACT FROM AUTHOR]

In this work, a multi-terminal hexagonal-framed magnetoelectric composite (HFMEC) made of amorphous FeBSi alloy (Metglas) ribbons and three sandwiched [011]-oriented PMN-PT single-crystal fibers (Pb(Mg1/3Nb2/3)O3-PbTiO3) arranged with a 120° interval is presented, and the directional magnetoelectric (ME) effect of the HFMEC operating in the L-T mode under a constant-amplitude AC magnetic field is investigated. It is found that the HFMEC exhibits threefold symmetric directional ME coupling in response to an applied in-plane DC magnetic field HDC, while each ME terminal shows a twofold symmetry due to the magnetization and demagnetization effect of HDC. Moreover, a valid formula for calculating the angular direction of the magnetic field is also presented. It is further revealed that the HFMEC exhibits a “V” shaped ME voltage output as a response to HDC due to the geomagnetic field (HGeo) effect, and the knee point of the curve literally reveals the magnitude of local HGeo, while the direction of HDC indicates a reverse direction of HGeo. The proposed HFMEC provides a great potential for a vector magnetometer as well as geomagnetic sensor application. [ABSTRACT FROM AUTHOR]

In this work, a multilayered-cylindrical piezoelectric shear actuator (MCPSA) operating in the d15 shear mode was presented for precision actuation under a large mechanical load. The actuator was made of Pb(Zr,Ti)O3 (PZT-51) piezoelectric ceramic rings, which were concentrically assembled together in electrically parallel connection with alternately positive and negative polarizations along the axial direction. Experimental results show that the acquired displacement amplitude at the center of the actuator along the axial direction is around 6.5 μm under the 1 Hz applied voltage of 400 Vpp/mm, and it stayed stably under a mechanical load up to 18 N, which is 7 times larger than that of the previously reported d15 shear actuator. The proposed actuator also shows good displacement linearity with a high resolution of 0.1 μm in responding to a step voltage, indicating its great potential for precision actuation under a large mechanical load. [ABSTRACT FROM AUTHOR]

We show that magnetoelectric (ME) laminate composites have characteristics of a previously conjectured, but unfound, fifth network circuit element—the Tellegen gyrator. Our findings establish that ME laminate composites (i) are nonreciprocal electrical elements, (ii) have significant nondissipative I-V conversion near a resonance frequency, and (iii) act like a unidirectional gyrator, i.e., an ideal Tellegen gyrator connected with a capacitor on one side and an inductor on the other. [ABSTRACT FROM AUTHOR]

We report a piezoelectric pseudo-bimorph actuator, which is made of only one single plate with interdigitated electrodes on both sides and polarized alternately in longitudinal direction. Like a bimorph actuator, it can also produce a large bending actuation based on anti-symmetrically longitudinal piezoelectric d33 strain effect under an applied electric field. The presented pseudo-bimorph actuator shows much better temperature stability than conventional piezoelectric bimorph actuators from room temperature to the depolarization temperature of the material due to lacking of interface strain loss. [ABSTRACT FROM AUTHOR]

The current paper reports a digital piezoelectric bimorph actuator having segmented electrodes and producing 2 to the nth power digital bending actuation in on/off switch mode and under a fix applied voltage. Correspondingly, a simple model for predicting digital actuation under applied coding voltage is also presented. Experimental results have confirmed that the proposed actuator can produce a linear digital displacement without a hysteresis loop. The proposed method is significant for open-loop high precise actuation. [ABSTRACT FROM AUTHOR]

Conventionally, piezoelectric ultrasonic linear actuators operate in longitudinal and bending combination (degenerate) modes for producing an elliptic motion which drives a slider moving linearly. With the increasing temperature, the degenerate mode will split into two separated modes again, resulting in piezoelectric actuators working to fail. Here, we report a miniature piezoelectric ultrasonic linear actuator made of Mn modified (1-x)BiScO3-xPbTiO3 piezoelectric ceramics operating in two orthogonal first bending modes (B1-B1). The B1-B1 mode linear actuator showed much better load and speed temperature stability than piezoelectric actuators operating in different combination mode in the investigated temperature range of room temperature to 200 °C. [ABSTRACT FROM AUTHOR]

Colossal low-frequency resonant magnetomechanical (MM) and magnetoelectric (ME) coupling effects have been found in a three-phase composite made of Pb(Zr,Ti)O3 ceramic fibers/phosphor copper-sheet unimorph and NdFeB magnets. The experimental results revealed that the ferromagnetic/elastic/piezoelectric three-phase composite with a cantilever beam structure could show huge bending MM coefficient of ∼145.9 × 10-3/Oe (unit in bending radian per Oe) and ME voltage coefficient of ∼16 000 V/cm·Oe at the first-order bending resonance frequency of ∼5 Hz. The achieved results related to ME effect are at least one order of magnitude higher over those of other ME materials and devices reported ever. The extremely strong MM and ME couplings in the three-phase composite are due to strong magnetic force moment effect induced by the interaction between NdFeB magnets and the applied magnetic field, and further resonant enhancement via the strain-mediated phosphor copper-sheet with a relatively high mechanical quality factor. [ABSTRACT FROM AUTHOR]

We report the epitaxial growth of multiferroic BiFeO3 (BFO) film on Si(001) substrate by pulsed laser deposition using CeO2/yttria-stabilized zirconia (YSZ) as buffer layers. The epitaxial relationships of the films were BFO(001)/CeO2(001)/YSZ(001)/Si(001) for out-of-plane and [110]BFO|[100]CeO2|[100]YSZ|[100]Si for in-plane, respectively. Capacitance-voltage characteristics of a Pt/BFO/CeO2/YSZ/p-Si capacitor exhibited clockwise hysteresis loops with a large memory window of 2.5 V at sweeping voltages of ±16 V. Both the high and low capacitance values showed no obvious degradation after 104 s. The improved retention property was attributed to the use of high-k CeO2/YSZ insulating layers that effectively eliminated the charge trapping in the heterostructure. [ABSTRACT FROM AUTHOR]

(0.95-x)BiScO3-xPbTiO3-0.05Pb(Cd1/3Nb2/3)O3 (BS-xPT-PCN) high temperature piezoelectric ceramics near the morphotropic phase boundary (MPB) have been synthesized by traditional solid-state reaction methods. The microstructural morphology, phase structure, and electrical properties of BS-xPT-PCN ceramics were investigated in detail. X-ray diffraction analysis indicated BS-xPT-PCN ceramics have a pure perovskite structure. The coexistence of rhombohedral and tetragonal phases at MPB composition enhanced the polarizability by the coupling between two dynamically equivalent energy states, resulting in the improved piezoelectric and ferroelectric properties at MPB vicinity. The BS-xPT-PCN (x = 0.60) ceramics possess the optimal piezoelectric and ferroelectric properties with d33 = 505pC/N, kp = 55.9%, kt = 36.5%, strain = 0.23% (under the electric field 37.5 kV/cm), and Pr = 39.7 μC/cm2. High temperature dielectric behaviors showed diffuse phase transition in BS-xPT-PCN ceramics. The Curie temperature Tc was found to increase from 371 °C to 414 °C with x increasing from 0.58 to 0.62. All these results together with the good thermal stabilities make the BS-xPT-PCN ceramics promising candidates for high temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

An analytical model of resonant magnetoelectric (ME) coupling in magnetostrictive (MS)-piezoelectric (PE) laminated composites in consideration of eddy-current effect in MS layer using equivalent circuit method is presented. Numerical calculations show that: (1) the eddy-current has a strong effect on ME coupling in MS-PE laminated composites at resonant frequency; and (2) the resonant ME coupling is then significantly dependent on the sizes of ME laminated composites, which were neglected in most previous theoretical analyses. The achieved results provide a theoretical guidance for the practice engineering design, manufacture, and application of ME laminated composites and devices. [ABSTRACT FROM AUTHOR]

High-valence Pr-doped BiFeO3 (BPF) multiferroic thin film was prepared by pulsed laser deposition on a Pt/TiO2/SiO2/Si substrate. X-ray diffraction analysis indicates that the BPF film is of pure phase with a polycrystalline perovskite structure. The BPF film exhibited enhanced multiferroic properties: (i) a rectangular-shaped electric hysteresis loop with a large Pr of 75 μC/cm2 and a low Ec of 250 kV/cm at Emax ∼620 kV/cm, (ii) a saturated magnetic hysteresis loop with a large Ms of 58 emu/cm3, and (iii) a fatigue-free behavior after being subjected to 1.2×109 switching cycles, which were superior to, in some aspects, those of La- or Nd-doped BiFeO3 films reported before. [ABSTRACT FROM AUTHOR]

In this letter, we investigate a multimodal system for simultaneous energy harvesting from stray magnetic and mechanical energies by combining magnetoelectric and piezoelectric effects. The system consists of a cantilever beam with tip mass and a magnetoelectric laminate attached in the center of the beam. At 2 Oe magnetic field and mechanical vibration amplitude of 50mg, both at frequency of 20 Hz, the system was found to generate open circuit output voltage of 8 VP.P.. An equivalent circuit model is proposed that predicts a summation effect for both mechanical and magnetic energies. [ABSTRACT FROM AUTHOR]

Here, the authors report a new type of geomagnetic field sensor based on the giant magnetoelectric effect in Metglas/piezoelectric-fiber laminates that are wrapped with a coil. These sensors can measure quite precisely the value of both the Earth’s magnetic field and its inclination. The geomagnetic field sensor does not require a dc magnetic bias and is driven by a 10 mA ac. Highly sensitive dc magnetic field variations of less than 10-9 T and angular inclinations of ≤10-5 deg can be detected, potentially offering opportunities for a small global positioning device [ABSTRACT FROM AUTHOR]

Giant magnetoelectric (ME) voltage and charge coefficients have been found in long-type composites of high-permeability magnetostrictive FeBSiC alloy ribbons laminated together with piezoelectric Pb(Zn1/3,Nb2/3)O3–7%PbTiO3 single crystal fibers. The maximum ME voltage and charge coefficients at low frequencies were 10.5 V/cm Oe and 1 nC/Oe under a notably low dc magnetic bias of 2 Oe; at resonance, these coefficients were dramatically increased to 400 V/cm Oe and 42 nC/Oe, respectively. These values are much higher, and the required dc magnetic bias much lower, than those of previously reported Terfenol-D based ME laminates. [ABSTRACT FROM AUTHOR]

Theoretically, the two-phase laminated configurations should have even much higher magnetoelectric (ME) effects—however, prior experimental studies have failed to find such an enhancement. Here, the authors report the unleashing of the potential of the (2-1) connectivity configuration: a piezofiber (one-dimension connectivity) layer laminated between two high-permeability magnetostrictive FeBSiC alloy ones (two-dimension connectivity) has near-ideal ME coupling. Very high ME effects of up to 22 V/cm Oe (4×10-7 s/m) at 1 Hz—an order of magnitude higher than the giant ones—have been found. [ABSTRACT FROM AUTHOR]

A giant current-to-voltage (I-V) gyration effect was found in magnetostrictive Tb1-xDyxFe2-y and piezoelectric Pb(Zr,Ti)O3 laminated composites. An equivalent circuit theory was developed for magnetoelectric gyration, which predicted that I-V conversion is reduced by a frequency transfer function ZR(f) and that the maximum occurs at resonance. A giant conversion coefficient up to 2500 V/A was predicted and confirmed. [ABSTRACT FROM AUTHOR]

Here, the authors report thin (<100 μm) and flexible magnetoelectric (ME) composites consisting of Metglas (high-μ magnetostriction) and polyvinylidene-fluoride (piezopolymer) layers laminated together. Both unimorph and three-layer configurations have been studied. The authors find that these ME laminates (i) require dc magnetic biases as low as 8 Oe to (ii) induce giant ME voltage coefficients of 7.2 V/cm Oe at low frequencies, and up to 310 V/cm Oe under resonant drive. [ABSTRACT FROM AUTHOR]

A promising generation of extremely low frequency magnetic field sensors, based on multilayer composites (MLCs) of magnetostrictive Terfenol-D (Tb1-xDyxFe2-y) and piezoelectric Pb(Mg1/3Nb2/3)O3–PbTiO3, has been developed. Our MLC magnetoelectric sensor presently shows a limit in (i) working frequency of ∼5×10-3 Hz; and (ii) magnetic field sensitivity of 10-7, 10-9, and 10-11 T for frequencies of f=10-2, 1, and 102 Hz, respectively. The results open up possibilities for sensitive low frequency passive magnetic anomaly detection. [ABSTRACT FROM AUTHOR]

It has been observed that a ring-type magnetoelectric laminate composite of circumferentially magnetized magnetostrictive Tb1-xDyxFe2 and circumferentially polarized piezoelectric Pb(Zr,Ti)O3 layers has a large magnetoelectric voltage gain effect, offering potential in high-power miniature transformer applications. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A hydrogen sensor is reported in which a small piezoelectric-sound-resonance-cavity (PSRC) is used as the sensing element. Detection utilizes sound resonance and acoustic property differences between H[SUB2] and air as a sensing mechanism. Changes in H[SUB2] concentration result in a shift of the sound-resonance state of the PSRC. Preliminary experiments have demonstrated a sensitivity limit of 8 ppm, a fast response time ∼1.5 second, and detection capabilities over a broad concentration range 10[SUP-5]

An acoustic position sensor, based on a piezoelectric-sound-resonance cavity (PSRC), is reported in which a resonance acoustic field is used as the sensing mechanism. It has been discovered that an inserted object or an object motion in the sound radiation field results in changes in the resonance state of the PSRC. Experiments have demonstrated a high position resolution in the axial direction, and also good sensitivity in the transverse. [ABSTRACT FROM AUTHOR]

A correction regarding the article “Piezoelectrically actuated vibrating flexible differential capacitances for electrostatic detection" with the authors address is presented.

A magnetoelectric (ME) flux gate sensor (MEFGS) consisting of piezoelectric PMN-PT single crystals and ferromagnetic amorphous alloy ribbon in a self-differential configuration is featured with the ability of weak magnetic anomaly detection. Here, we further investigated its ME coupling and magnetic field detection performance in vibration noise circumstance, including constant frequency, impact, and random vibration noise. Experimental results show that the ME coupling coefficient of MEFGS is as high as 5700 V/cm*Oe at resonant frequency, which is several orders magnitude higher than previously reported differential ME sensors. It was also found that under constant and impact vibration noise circumstance, the noise reduction and attenuation factor of MEFGS are over 17 and 85.7%, respectively. This work is important for practical application of MEFGS in real environment. [ABSTRACT FROM AUTHOR]

We report a piezoelectric standing wave linear ultrasonic motor with double driving tips for generating precision motion. The motor's piezoelectric actuator was made of a simple Pb(Zr,Ti)O3 square-plate (15 × 15 × 2 mm3) operating in a single face-diagonal-bending standing wave mode to produce symmetric, bi-directional linear motion. The motor generated a driving force of 3.0 N and a moving speed of up to 165 mm/s under a relatively low applied electric field of 75 Vpp/mm at a resonance frequency of 141.5 kHz. This motor is superior to those previously reported because of the double friction-tip standing wave driving mechanism and the operating mode. [ABSTRACT FROM AUTHOR]