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The magnetoelectric (ME) laminated composite is an important multifunctional material for developing novel electronic devices that provide many applications in sensing, energy conversion, filtering, etc. Following the previous investigations, this paper proposes theoretical modeling to study the relationship between a bar-shaped ME laminated composite's enhancement effects and material properties. This composite has a breakthrough idea that produces two operating modes (sensing and transducing) in the same working process. Our analyses are based on the magneto-elastic-electric equivalent circuit and mechanical connections between an ME laminated composite and a piezoelectric plate. Our works not only predicted the ME outputs against magnetic field bias change but also studied the relationship of the length ratio between the ME laminated composite and the piezoelectric plate. The results showed that the ME outputs of the transduction mode are much bigger than the sensing mode at resonance, which strongly depended on the dimension and the physical properties of the sample. These findings provided a promising gate for the researchers to develop a single electronic device that combined sensing and power conversion.

Tunability in magnetoelectric (ME) gyrators is of importance for realizing controllable energy-efficient electronics. Here, we investigated a novel passive control method that exhibits a high frequency tunability of up to 370 Hz using a non-power-consuming (passive) capacitor approach. The method requires zero external controllable power as the frequency is changed. This tuning does not decrease the power conversion efficiency (86%) of the gyrator. Our results indicate that the internal mechanical reactive components need to be changed by passive external capacitors, which proves to be an effective way by which gyrators can achieve high tunability and retain high power conversion efficiency. This article opens an approach toward the design of new tunable circuit components.

X-ray diffraction (XRD) reciprocal space mapping (RSM) was used to investigate how nanograted electrodes affect the nanodomain distribution and average crystal structure in near-surface regions of poled Pb(Mg1/3Nb2/3)O3-30%PbTiO3 (PMN-30PT) single crystals. The RSM scans revealed a transverse broadening along the (H00) direction, which was quite different from that of either the rhombohedral (R) or monoclinic A (MA) phase. This broadening provides evidence of a non-uniform distribution of tilt angles between neighboring nanodomains, induced by a gradient in the applied electric field (E). Investigations of the front and back surfaces of the crystals revealed significant differences in the RSM scans. Gradients in the domain distribution and apparent symmetry may extend throughout the crystal thickness. The data evidence changes in the nanodomain distribution that results in adaptations of the average symmetry.

Magnetoelectric (ME) gyrators are unique circuit elements capable of direct conversion of the current to voltage or vice versa. In order to understand the power conversion and loss processes in the gyrators, an equivalent input loss factor has been developed in this paper based on Mason's model (equivalent circuit model). This factor serves to understand the loss transferring mechanism and to evaluate the conversion efficiency for the electric power in ME gyrators. Studies have been carried out for modeling the power conversion in both the solenoid and the ME core. Several important factors have been proposed and discussed to enhance the conversion efficiencies in the electric–magnetic–mechanical three-phase conversion process. A simplification of our equations reveals that the efficiency of the ME gyrator is related to the product of the effective coupling ( k2 $_{\text{eff, m}}$ ) and mechanical quality ( Q mech). According to our model, magnetic and electric materials with high k $_{\text{eff, m}}$ and Q mech values are the key ingredients to enhance the efficiency of ME gyrators. We have successfully realized a power efficiency of 92% based on a Metglas/hard-PZT ME gyrator, which showed a good correlation to the predicted values.

A Magneto-Electric (ME) gyrator with a superior power efficiency of 95 % has been achieved based on a two-phase solid-state ME laminate. This ME gyrator consists of a winding coil that generates a magnetic field as the first step to realize electromagnetic energy transfer. A magneto-electric composite, serving as the second step, then converts the power from magnetic to electric forms. The laminate consists of two iron-cobalt based amorphous alloy layers bonded to a lead zirconate titanate plate. It has a giant magneto-electric coefficient of around 2200 (V/cm)/Oe at its mechanical resonant frequency (≈ 44 kHz) in structure. Approaching methods based on maximum power transfer (MPT) efficiency theory and the equivalent loss factor (ELF) from the input port have been introduced to evaluate the power efficiency of the ME gyrator. The expected MPT efficiency is 96.5 % at a power volume density of 0.1 W/in3 (6.1 mWatt/cm3), and 93.2 % up to 20 W/in3 (1.22 W/cm3). The ELF explains that the magnetomechanical conversion efficiency is related to the volume of the magnetic phase which is the dominating term in the power efficiency.

Magnetoelectric (ME) power efficiency is a more important property than the ME voltage or the current coefficients for power conversion applications. This paper introduces an analytical model that describes the relation between the external magnetic field and the power efficiency in layered ME composites. It is a two-phase model. The first fragment establishes the expression between the magnetic field strength and the temperature increase within an operating period. It uses a magneto-elasto-electric equivalent circuit model that was developed by Dong et al. Following previous investigations; the main loss source is the mechanical power dissipation. The second fragment links the power efficiency and the temperature increase in a heat-balanced system. This method is generally used by researchers in the piezoelectric field. The analytical model and the experimental data shows that the decrease of the power efficiency in a laminated composite is between 5% and 10% for a power density of 10 W/in3 (0.61 W/cm3) to 30 W/in3 (1.83 W/cm3). The failure mechanism/process of ME composites under high power density can be estimated/monitored by the proposed method for ME composites in practical applications. Published version

This paper reports a dual-resonance power transfer effect and a dual-resonance I-V conversion for a bar-shaped ME gyrator made from a hard Pb(ZrxTi1−x)O3 (PZT) ceramic bar having a transverse polarization and a Tb0.3Dy0.7Fe1.92 (Terfenol-D) magnetostrictive alloy bar having a longitudinal magnetization bonded along their cross-section areas. A bar-shaped provides several advantages to a ME gyrator; such as dual resonance frequency along its length direction, as well as half-wave and full-wave vibration modes; reduced laminate bonding area avoiding adhesive breakdown; and ease of fabrication. The reported magnetoelectric gyrator effect originates from the mechanically mediated resonance piezoelectric and magnetostrictive effects in the PZT and Terfenol-D bars, respectively. We studied the influence of the length ratio between the Terfenol-D and piezoelectric bars. A power efficiency of 69.4% was obtained at the half wavelength resonance of 21.47kHz under optimal H Bias=1000 Oe and low power conditions. Under higher power drive of 8W/in3, an efficiency of 60.2% was found. This dual-resonance ME gyrator effect offers much promise in power transfer devices for power electronic applications.

We have deposited self-assembled BiFeO3-CoFe2O4 (BFO-CFO) thin films on (100)-oriented SrRuO3-buffered Pb(Mg1/3Nb2/3)0.62Ti0.38O3 (PMN-38PT) single crystal substrates. These heterostructures were used for the study of real-time changes in the magnetization with applied DC electric field (E DC ). With increasing E DC , a giant magnetization change was observed along the out-of-plane (easy) axis. The induced magnetization changes of the CFO nanopillars in the BFO/CFO layer were about ΔM/M rDC = 93% at E DC = −3 kv/cm. A giant converse magnetoelectric (CME) coefficient of 1.3 × 10−7 s/m was estimated from the data. By changing E DC , we found multiple(N ≥ 4) unique possible values of a stable magnetization with memory on the removal of the field.

International audience; Over the past two decades, magnetoelectric (ME) composites and their devices have been an important topic of research. Potential applications ranging from low power sensing to high power converters have been investigated. This review, first, begins with a summary of multiferroic materials that work at room temperature. Such ME materials are usually in composites, and their ME effect generated as a product property of magnetostrictive and piezoelectric composite layers. After that, mechanisms, working principles, and applications of ME composites from heterostructural uncooled magnetic sensors, energy harvesters to highly efficient power converters will be discussed. First, the development of ME sensors in terms of materials and structures to enhance their sensitivities and to reduce noise level is reviewed and discussed. Second, the structure of ME-based energy harvesters is discussed and summarized. Third, the development ME gyrators is summarized for power applications, including the current/voltage conversion, power efficiency, power density and figures of merit. Results demonstrate that our ME gyrator has the ability to satisfy the needs of power conversion with superior efficiency (>90%), offering potential uses in power electronic applications.

The coupling between the tetragonal phase (T-phase) of BiFeO3 (BFO) and CoFe2O4 (CFO) in magnetoelectric heterostructures has been studied. Bilayers of CFO and BFO were deposited on (001) LaAlO3 single crystal substrates by pulsed laser deposition. After 30 min of annealing, the CFO top layer exhibited a T-phase-like structure, developing a platform-like morphology with BFO. Magnetic hysteresis loops exhibited a strong thickness effect of the CFO layer on the coercive field, in particular along the out-of-plane direction. Magnetic force microscopy images revealed that the T-phase CFO platform contained multiple magnetic domains, which could be tuned by applying a tip bias. A combination of shape, strain, and exchange coupling effects are used to explain the observations. U.S. Department of Energy [DE-FG02-06ER46290]; Air Force Office of Scientific Research [FA9550-16-1-0001] This work was supported by the U.S. Department of Energy under contract DE-FG02-06ER46290 (MG and DDV), and by the Air Force Office of Scientific Research under contract FA9550-16-1-0001 (JFL). The authors also thank Dr. Christopher Winkler of the ICTAS Nanoscale Characterization and Fabrication Laboratory, Virginia Tech for the assistance of the TEM measurement.

We have deposited self-assembled BiFeO3-CoFe2O4 (BFO-CFO) thin films on (100)-oriented SrRuO3-buffered Pb(Mg1/3Nb2/3)0.62Ti0.38O3 (PMN-38PT) single crystal substrates. These heterostructures were used for the study of real-time changes in the magnetization with applied DC electric field (EDC). With increasing EDC, a giant magnetization change was observed along the out-of-plane (easy) axis. The induced magnetization changes of the CFO nanopillars in the BFO/CFO layer were about ΔM/MrDC = 93% at EDC = −3 kv/cm. A giant converse magnetoelectric (CME) coefficient of 1.3 × 10−7 s/m was estimated from the data. By changing EDC, we found multiple(N ≥ 4) unique possible values of a stable magnetization with memory on the removal of the field.

In present work, La0.6Sr0.4CoO3 (LSCO)-buffered 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMNT) thin film was grown on Pt/Ti/SiO2/Si substrate by using pulsed laser deposition. The introduction of the conductive LSCO layer can effectively depress the formation of pyrochlore phase and improve the crystallization quality of perovskite PMNT thin film ascribed to the similar crystal structure and lattice constant. Enhanced ferroelectric and dielectric properties were obtained with the saturated polarization Ps of ∼44 μC/cm2, remanent polarization Pr of ∼16.5 μC/cm2, dielectric constant e 33 T / e 0 of ∼2833 at 1 kHz, and dielectric tunability of 67% under ∼10 kV/mm. All these make it a potential candidate for MEMS devices.

Background: Exposure to smoking-related cues leads to increased urge to smoke in regular cigarette smokers and resisting these urges requires considerable self-control. Purpose: Adopting a resource depletion model, two studies tested the hypothesis that resisting smoking urges depletes self-control resources. Methods: Adopting a within-participants randomized cross-over design, participants (study 1, N = 19; study 2, N = 32) were exposed to smoking-related (study 1: smoking images; study 2: cigarette cue-exposure task) and neutral (study 1: neutral images; study 2: drinking-straw task) cues with presentation order randomized. After each cue set, participants completed self-control tasks (study 1: handgrip task; study 2: handgrip and Stroop tasks), performance on which constituted dependent measures of self-control. Results: Self-control task performance was significantly impaired when exposed to smoking-related cues compared to neutral cues. No significant presentation-order effects, or interaction effects between stimulus and presentation order, were found. Conclusions: Findings corroborate our hypothesis that resisting smoking urges depletes cigarette smokers' self-control resources and suggests that self-control capacity is governed by a limited resource. © 2013 The Society of Behavioral Medicine.

In this study, the dielectric, ferroelectric and strain behaviors of 0.35Pb(In1/2Nb1/2)O3–0.35Pb(Mg1/3Nb2/3)O3–0.30PbTiO3 (0.35PIN–0.35PMN–0.30PT or PIMNT35/35/30) single crystal with different crystallographic orientations were investigated as a function of temperature. The Curie temperature TC and rhombohedral to tetragonal phase transition temperature Trt were risen up to 188 °C and 120 °C, respectively. The coercive field EC and remnant polarization Pr for 〈0 0 1〉 and 〈1 1 0〉 oriented crystals were found to be 5.8 kV/cm, 27.5 μC/cm2 and 8.5 kV/cm, 38.7 μC/cm2 at room temperature, respectively. The polarization data were obtained from the hysteresis loops of the crystal measured in a wide temperature range. The unipolar strain level was found to be 0.65% at an electric field of 32 kV/cm, with piezoelectric strain coefficient d33 ∼ 2000 pC/N for 〈0 0 1〉 oriented crystal. Besides, the intermediate metastable state was induced at an electric field of 12.5 kV/cm for 〈1 1 0〉 oriented crystal, which can be utilized in large power transducers such as sonar and actuator.

A ternary solid solution (0.935-x)Bi0.5Na0.5TiO3–0.065BaTiO3–xSrTiO3 was designed and fabricated using a conventional fabrication process. Temperature and composition dependence of the ferroelectric, dielectric, and piezoelectric properties were systematically investigated and a schematic phase diagram was established. The SrTiO3 substitution was found to induce a transition from ferroelectric to relaxor pseudocubic phases. Around a critical composition x of 0.22, large strain response of ~0.2% (under a moderate field of 4 kV/mm) with normalized strain of 490 pm/V was obtained. The large unipolar strain response would be of great interest for environmental-friendly “on-off” actuators.

New type of Fe(Mn)/Mn(7)C(3)/graphite nanocapsules was prepared by a modified arc discharge technique in ethanol vapor, with Fe(Mn) solid solution nanoparticles as the core, Mn(7)C(3) as the inner shell, and graphite as the outer shell. The Cole-Cole semicircle approach was adopted to explain the ternary dielectric resonance, due to a cooperative consequence of the core/shell/shell interfaces and the dielectric Mn(7)C(3) and C shells. A remarkable increase in the anisotropy energy led to a shift in the natural resonance frequency to 6.6 GHz. Dielectric losses come from the ternary dielectric resonance while magnetic losses were from the magnetic natural resonance. An optimal reflection loss (RL) of -142.1 dB was observed at 12 GHz for 5.0 mm thickness layer. RL exceeding -10 dB was obtained at 6.6-18 GHz for 1.4 mm thickness, covering the whole X band (8-12 GHz), Ku band (12-18 GHz), and some of C band (6.6-8.0 GHz). RL exceeding -20 dB was found at 6-10.6 GHz for 2.2 mm thickness. (C) 2011 Elsevier B. V. All rights reserved.

In this study, the temperature and composition dependence of the dielectric, ferroelectric properties, and polarization current characteristics of the (0.935 − x)Bi0.5Na0.5TiO3–0.065BaTiO3–xSrTiO3 (BNBSTx) with x ranging from 0.02 to 0.22 were systematically investigated. At elevated temperature the BNBSTx solid solution with x 0.18, which may be related with the formation of certain sublattices in the complex solid solution.

Pseudo-1-3 magnetostrictive particulate composites consisting of light rare earth (Sm and Nd)-based magnetostrictive Sm(1-x)Nd(x)Fe(1.55) particles with the Nd content x of 0-0.56 and randomly distributed sizes of 10-180 mu m membedded and aligned in a passive epoxy matrix are fabricated using the particulate volume fraction of 0.5. The quasistatic magnetomechanical properties of the composites are investigated and the results are compared with their monolithic alloys for various x. The composites exhibit similar qualitative trends in properties with the alloys for all x. The Sm(0.92)Nd(0.08)Fe(1.55) composite shows a large unsaturated magnetostriction lambda of -530ppm at 500 kA/m and a high piezomagnetic coefficient d(33) of -2.0 nm/A at 100 kA/m as a result of the magnetocrystalline anisotropy compensation between Sm(3+) and Nd(3+) ions in the Sm(0.92)Nd(0.08)Fe(1.55) alloy. (C) 2011 Elsevier B.V. All rights reserved.

Magnetomechanical conversion abilities of several Nickel, Metglas and Terfenol-D were investigated by using a constructed magnetic power path with two winding coils. We characterized the magnetostriction efficiency as a function of power density with the optimal load resistor and magnetic bias. We found a high magnetomechanical conversion efficiency of 95% and 90% under low power drive for a Metglas layer and a Metglas/Pb(ZrXTi1-X)O3 composite, respectively.

This report is on a new class of magnetostatically tunable magneto-impedance and magneto-capacitance devices based on a composite of ferromagnetic Metglas and ferroelectric lead zirconate titanate (PZT). Layered magneto-electric (ME) composites with annealed Metglas and PZT were studied in a longitudinal in-plane magnetic field-transverse electric field (L-T) mode. It was found that the degree of tunability was dependent on the annealing temperature of Metglas. An impedance tunability (ΔZ/Z0) of ≥400% was obtained at the electromechanical resonance (EMR) frequency (fr) for a sample with Metglas layers annealed at Ta = 500oC. This tunability is a factor of two higher than for composites with Metglas annealed at 350oC. The tunability of the capacitance, (ΔC/C0), was found to be 290% and -135k% at resonance and antiresonance, respectively, for Ta = 500oC. These results provide clear evidence for improvement in static magnetic field tunability of impedance and capacitance of ME composites with the use of annealed Metglas and are of importance for their potential use in tunable electronic applications.

Heterostructures of BiFeO3/Pb(Mg1/3Nb2/3)O3-30%PbTiO3 (BFO/PMN-30PT) were fabricated by pulsed laser deposition. Electric fields (E) were applied on the PMN-30PT substrates along the in-plane and out-of-plane directions, and the induced strain of BFO was measured as a function of E by X-ray diffraction. Reciprocal space maps along the (110) zone axis evidenced that a monoclinic MA phase was induced in both PMN-PT and BFO, where the dominate domain structures could be switched between biaxial directions under application of in-plane E. Studies were done for films prepared under different laser energy densities (LED), in order to optimize the in-plane strain of BFO. A relatively low LED of 1 J/cm2 produced a better BFO thin film with larger in-plane strain.

A lead-free magnetoelectric (ME) laminate composite consisting of thickness-polarized piezoelectric Mn-doped Na 0.5 Bi 0.5 TiO 3 –BaTiO 3 single crystal and length-magnetized magnetostrictive Tb 0.3 Dy 0.7 Fe 1.92 alloy (L-T mode), have been fabricated and its ME properties has been evaluated. The results revealed that the lead-free composite has linear magnetic-electric response in excess of 1.32 V/cm Oe at low frequency over the range of 10 −7 T H ac −3 T, the ME coefficient dramatically increases and reaches the maximized value of 18 V/cm Oe near the resonance frequency of 160 kHz. This heterostructure opens up the possibility for environment-friendly magnetic sensors.

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 1/3 Nb 2/3 )O 3 –0.3PbTiO 3 (PMN–PT) crystal plate and a length-magnetized magnetostrictive Tb 0.3 Dy 0.7 Fe 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.

An article of this title was published in the Journal of Alloys and Compounds, 509 (2011) 9071–9075. Unfortunately, a computational rror has occurred which causes the results described in part of the abstract, in part of Section 3 of the main text, in Fig. 3, in part of the onclusion, and in references in the published article to be wrong. The corrected abstract, the corrected text in Section 3, the corrected ig. 3, the corrected conclusion, and the corrected references are displayed below: In abstract, the last two sentences should be corrected as “An optimal reflection loss (RL) of −35.5 dB was observed at 12 GHz for 5.0 mm hickness layer. RL exceeding −2.5 dB was obtained at 6.6–18 GHz for 1.4 mm thickness, covering the whole X band (8–12 GHz), Ku band 12–18 GHz), and some of C band (6.6–8.0 GHz). RL exceeding −5 dB was found at 6–10.6 GHz for 2.2 mm thickness.” The last two paragraphs in Section 3 should be corrected as follows: To further examine the microwave absorption abilities of the Fe(Mn)/Mn7C3/C nanocapsules, RL as a function of absorbing thickness d nd frequency f were calculated, as shown in Fig. 3, according to Eq. (1). The optimal RL or the dip in RL corresponds to the occurrence of he maximum absorption or the minimum reflection of the microwave power for the particular thickness [34]. As shown in Fig. 3(a), an ptimal RL of −35.5 dB, corresponding to almost 100% absorption, is observed at 12 GHz for 5.0 mm thickness layer. The intensity and the requency at the reflection loss minimum depend on the properties and thickness of the materials [34]. It is worth noting that the number f dips increases with an increase in sample thickness. It can be seen that there is only one dip for 1–3 mm and the dip shifts to the lower requency side with increasing thickness of the layer, while two complete dips can be observed for 3–5 mm. The occurrence of the dips is ound to be due to a successive odd number multiple of the quarter wavelength ( ) thickness of the material or d = n /4 (n = 1, 3) [34]. The absorbing thickness of 5.0 mm is too thick for the rapid development in electronic industry. From the view point of practical use he upper limit of absorbing thickness should be 3.0 mm. As shown in Fig. 3(b), RL exceeding −2.5 dB is obtained at 6.6–18 GHz for 1.4 mm hickness, covering the whole X band (8–12 GHz), Ku band (12–18 GHz), and some of C band (6.6–8.0 GHz). Also, RL exceeding −5 dB is found t 6–10.6 GHz for 2.2 mm thickness. In addition, an optimal RL reaching −13.5 dB is seen at 7 GHz for 2.6 mm thickness. Bandwidth of RL xceeding −2.5 dB is sufficiently widened in Fe(Mn)/Mn7C3/C due to the ternary dielectric relaxation and the enhanced natural resonance rom the special core/shell/shell microstructure. The conclusion should be corrected as: Fe(Mn)/Mn7C3/C nanocapsules have been synthesized by a modified arc discharge technique, with Fe(Mn) nanoparticles as the core, n7C3 as the inner shell, and C as the outer shell. The nanocapsules have exhibited the excellent microwave absorption properties at

The current research tested the hypothesis that individuals engaged in long-term efforts to limit food intake (e.g., individuals with high eating restraint) would have reduced capacity to regulate eating when self-control resources are limited. In the current research, body mass index (BMI) was used as a proxy for eating restraint based on the assumption that individuals with high BMI would have elevated levels of chronic eating restraint. A preliminary study (Study 1) aimed to provide evidence for the assumed relationship between eating restraint and BMI. Participants (N = 72) categorized into high or normal-range BMI groups completed the eating restraint scale. Consistent with the hypothesis, results revealed significantly higher scores on the weight fluctuation and concern for dieting subscales of the restraint scale among participants in the high BMI group compared to the normal-range BMI group. The main study (Study 2) aimed to test the hypothesized interactive effect of BMI and diminished self-control resources on eating behavior. Participants (N = 83) classified as having high or normal-range BMI were randomly allocated to receive a challenging counting task that depleted self-control resources (ego-depletion condition) or a non-depleting control task (no depletion condition). Participants then engaged in a second task in which required tasting and rating tempting cookies and candies. Amount of food consumed during the taste-and-rate task constituted the behavioral dependent measure. Regression analyses revealed a significant interaction effect of these variables on amount of food eaten in the taste-and-rate task. Individuals with high BMI had reduced capacity to regulate eating under conditions of self-control resource depletion as predicted. The interactive effects of BMI and self-control resource depletion on eating behavior were independent of trait self-control. Results extend knowledge of the role of self-control in regulating eating behavior and provide support for a limited-resource model of self-control. © 2013 Hagger et al., published_or_final_version