Metglas Layers Research Articles

High Output, Biocompatible, Fully Flexible Fiber‐Based Magneto‐Mechano‐Electric Generator for Standalone‐Powered Electronics

AbstractHarvesting magnetic noise fields around power cables emerges as an attractive approach due to its potential as a renewable and ubiquitous energy source for powering wireless sensor networks (WSNs) in IoT applications, miniature electronics, and implantable medical devices. Flexible polymer‐based magneto‐mechano‐electric (MME) generators gain attention for their effectiveness in magnetic energy harvesting owing to their durability and flexibility. In this study, a lead‐free, flexible MME generator is developed by using Polyvinylidene fluoride (PVDF)‐Aluminium nitride (AlN)‐nanofiber composites fabricated via electrospinning with different AlN compositions and integrated with a magnetostrictive Metglas layer that offers self‐bias characteristics. The MME generator is modeled using COMSOL Multiphysics to analyze the magnetic flux density distribution over the Metglas surface and the piezoelectric effect of the nanofiber composites, with the simulation results aligning well with the experimental data. The optimized, flexible MME generator, incorporating 15 wt.% of AlN in the PVDF/Metglas composite, achieves an open‐circuit voltage of 18.5 V and a power density of 0.93 mW‐cm−3 when exposed to an Alternating Current (AC) magnetic noise field of 6 Oe at a resonance frequency of 50 Hz. The generated power is sufficient to operate LEDs and sensor. This newly developed lead‐free, flexible MME generator shows significant promise for advanced applications in self‐powered WSNs.

Assessing mechanical and stray magnetic field energy harvesting capabilities in lead-free PVDF/BCT-BZT composites integrated with metglas

The exploration of energy harvesting encompasses a wide array of sources, with a specific focus on recovering mechanical and magnetic energy from overlooked outlets, driving current research endeavours. In this study, we developed highly flexible Magneto-Mechano-Electric (MME) harvesters by combining poly(vinylidene fluoride) (PVDF)/barium calcium zirconium titanate (BCT-BZT) composite films with metglas. The flexible piezoelectric polymer-ceramic composite films were fabricated using a solvent casting technique. The high piezoelectric BCT-BZT fillers were synthesized through a sol-gel reaction route. A thorough analysis was carried out on these composites to evaluate their structural, functional, microstructural, and dielectric properties. The composite film loaded with 20 wt% BCT-BZT filler achieved a 78 % β-phase with a significant enhancement in the dielectric properties, resulting in a high permittivity∼40 and low dielectric loss. Employing these films, we engineered nanogenerators capable of converting mechanical energy into electrical energy, yielding an output voltage of 11 V. Thereafter, to harvest mechanical and stray magnetic fields, we developed a MME generator comprising a magnetic Metglas layer and PVDF-BCT-BZT composite and achieved an output voltage of 3.3 V with a power density of 85 μW/m2 when subjected to an AC magnetic field of 5 Oe. Furthermore, the MME generator has demonstrated the ability to charge various capacitors showcasing its potential for usage in self-powered, non-contact, and implantable devices.

A flexible magneto-electric sensor with enhanced performance through flower-shaped BTO fillers in P(VDF-TrFE) matrix

A flexible magneto-electric(ME) sensor, incorporated a piezoelectric layer with flower-shaped Barium Titanate (BTO) fillers(referred as BTFs) in P(VDF-TrFE) matrix and a ferromagnetic Metglas layer[P(VDF-TrFE)@BTFs/Metglas], has been developed. The introduction of flower-shaped BTO fillers enhances the β-phase of P(VDF-TrFE), leading to improved piezoelectric properties. The unique flower-like structure provides a larger specific surface area and increased grain size, resulting in interface asymmetry and creating a more intricate contact interface between P(VDF-TrFE) and Metglas. This strengthens the interaction and facilitates strain transmission, ultimately enhancing the ME coupling performance of the system. Moreover, the flexible ME detector exhibits superior magnetic field detection capabilities, demonstrating enhanced sensitivity and resolution compared to its spherical BTO counterpart. The devices display exceptional linearity, indicating the potential for practical application as magnetic sensors. This research expands the understanding of the complex relationship between filler morphology and P(VDF-TrFE) properties, presenting promising potential for high-performance flexible ME devices.

Modeling and performance analysis of resonant self-biased magnetoelectric transducers

Compared with single-phase multiferroic materials, magnetoelectric (ME) composites composed of piezoelectric and magnetostrictive materials have great ME coupling, and have received widespread attention in various application fields. The application of ME devices in wireless power transfer (WPT) is attractive due to their compactness and ability to operate at lower frequencies than conventional coils. However, traditional ME composites rely on permanent magnets or electromagnets to provide biased magnetic fields, thus leading to problems such as high noise, large size, and high cost, which significantly hinder the advancement of miniaturized and high-performance ME devices. To solve this problem, a self-biased ME laminated structure based on the magnetization grading effect is proposed in this work. Using the equivalent magnetization and nonlinear magnetostrictive constitutive relationship, a finite element simulation model for a self-biased ME transducer operating in L-T mode is constructed. The ME coupling performances without DC bias in bending vibration mode and stretching vibration mode are studied. Based on the model, the corresponding experimental samples are prepared for measurement. The measurement results are in agreement with the simulation data, thereby validating the accuracy and effectiveness of the model. The measured results show that the Metglas/Galfenol/PZT-5A structure can exhibit more significant self-biased ME effect under the stretching resonance mode than under bending resonance mode. Its ME coefficient attains a notable value of 10.7 V·cm<sup>–1</sup>·Oe<sup>–1</sup> at 99.4 kHz, while ME power coefficient reaches 5.01 μW·Oe<sup>–2</sup> at 97.9 kHz. Its on-load ME power coefficient can reach up to 4.62 μW·Oe<sup>–2</sup> at 99.3 kHz without impedance matching. When an external bias magnetic field of 25 Oe is applied, these performance indexes increase significantly to 47.06 V·cm<sup>–1</sup>·Oe<sup>–1</sup> at 99.4 kHz and 82.13 μW·Oe<sup>–2</sup> at 99.0 kHz, respectively. The simulation results further show that the performance of the self-biased ME transducer can be significantly improved by increasing the thickness of the high permeability layer. For example, by increasing the Metglas layer thickness from 30 μm to 90 μm, both the ME coefficient and ME power coefficient increase rapidly by 2.47 times and 6.96 times the original values, respectively. Self-biased ME transducers effectively reduce the dependence on external bias magnetic field, thereby providing a good approach for applying and developing ME composites in low-frequency WPT systems.

Magnetoelectric MEMS Magnetic Field Sensor Based on a Laminated Heterostructure of Bidomain Lithium Niobate and Metglas.

Non-contact mapping of magnetic fields produced by the human heart muscle requires the application of arrays of miniature and highly sensitive magnetic field sensors. In this article, we describe a MEMS technology of laminated magnetoelectric heterostructures comprising a thin piezoelectric lithium niobate single crystal and a film of magnetostrictive metglas. In the former, a ferroelectric bidomain structure is created using a technique developed by the authors. A cantilever is formed by microblasting inside the lithium niobate crystal. Metglas layers are deposited by magnetron sputtering. The quality of the metglas layers was assessed by XPS depth profiling and TEM. Detailed measurements of the magnetoelectric effect in the quasistatic and dynamic modes were performed. The magnetoelectric coefficient |α32| reaches a value of 492 V/(cm·Oe) at bending resonance. The quality factor of the structure was Q = 520. The average phase amounted to 93.4° ± 2.7° for the magnetic field amplitude ranging from 12 to 100 pT. An AC magnetic field detection limit of 12 pT at a resonance frequency of 3065 Hz was achieved which exceeds by a factor of 5 the best value for magnetoelectric MEMS lead-free composites reported in the literature. The noise level of the magnetoelectric signal was 0.47 µV/Hz1/2. Ways to improve the sensitivity of the developed sensors to the magnetic field for biomedical applications are indicated.

Low-Frequency Magnetic Field Detection Using Magnetoelectric Sensor With Optimized Metglas Layers by Frequency Modulation

It is an important engineering challenge to detect a weak magnetic field <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${H}_{AC}$ </tex-math></inline-formula> at low frequencies (1-100 Hz) due to large noise. In this work, a magnetoelectric (ME) sensor using single-crystal quartz material as the piezoelectric phase and optimized magnetostrictive layers has been presented to sense the low-frequency magnetic field signals. Firstly, the ME response properties of the bulk Metglas/quartz/Metglas laminate sensor were studied and a high ME coefficient of 3038 V/(cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula> Oe) has been attained in its electromechanical resonance frequency. With frequency modulation technique, which a magnetic low-frequency signal can be transferred to around resonance frequency of the sensor, the proposed sensor was used to detect the low frequency magnetic field signals under zero bias conditions. It is experimentally found that the absolute resolution with respect to a 1 Hz magnetic field can be decreased as low as 44 pT ± 1.41 pT with 20 layers of Metglas. More importantly, the ME coefficients with different layers under zero bias and the effect of Metglas layers on the limit of the detection at 1 Hz also have been investigated. The results show that the limit of the detection at 1 Hz can be decreased to 10 pT ± 0.32 pT with 14 layers of Metglas which indicates an enhancement by 4.4 times in comparison with 20 layers. This simple bulk Metglas/quartz/Metglas laminate sensor with optimized layers has a great potential to be used for low-frequency bio-magnetic signals measurement at room temperature.

Improved sensitivity and bandwidth of hybrid magnetic sensor based on electrically modulated amorphous magnetic alloy/piezoelectric composite

This study reports an electrically modulated dc and low frequency magnetic sensor with high sensitivity and wide bandwidth. It is based on multiferroic composites consisting of amorphous magnetic alloy Metglas/piezoelectric transformer (i.e., Pb(Zr,Ti)O3/Pb(Zr,Ti)O3)/Metglas layers winded with capacitor connected excitation coils and pickup coils. By electrically exciting the piezoelectric transformer winded with coils, the periodically induced stress and magnetic field modulate the magnetization of Metglas simultaneously and cause the change of magnetic flux within the pickup coils. The output voltage is further enhanced with the resonant converse magnetoelectric (CME) and mutual inductance effects at the mechanical and LC resonance frequency, respectively. Furthermore, the asymmetric wide bandwidth property of hybrid magnetic sensor provides the enhanced low frequency magnetic field sensitivity with negligible extra power consumption compared to the CME effect. When the magnetic sensors are excited with 5 V voltage at the resonance frequency and applied with 10 Hz magnetic field, the hybrid magnetic sensor achieves the maximum magnetic field sensitivity of 2.20 V/Oe and this is about 4.89 times as high as that of CME effect (0.45 V/Oe). The limit of detection for 10 Hz magnetic field is also noticeably improved from 2.97 nT for CME effect to 590pT for the hybrid magnetic sensor.

Hybrid magnetoelectric converter

The article is devoted to the study of a hybrid magnetoelectric voltage converter. The article deals with the magnetoelectric structure of the converter with its design features. The measuring stand with the calculation of the converter parameters is also described and the measurement results are given. In the manufacture of the ME element, materials such as piezoelectric PZT and magnetostrictive amorphous alloy Metglas were used. ME is a layered element, which consists of a PZT plate with electrodes applied to the lateral surfaces and one or more Metglas layers. The Metglas plates are connected to the piezoelectric using an adhesive bond. In experimental studies, the number of Metglas layers varied from one to three. The article discusses the design of the converter and the choice of the most optimal of the ones under study. As a result of the study, the lowest indicators were found for a converter without a core, the more Metglas layers, the better the characteristics of the converter. The ME element at the resonant frequency converts energy much better (the conversion power was about 130 μW) than the design of a conventional converter, and also a hybrid converter based on a series switching circuit gives an even greater gain in energy conversion (the conversion power was about 180 μW).

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.

Giant Self-biased Magnetoelectric Effect in Pre-biased Magnetostrictive–Piezoelectric Laminate Composites

In this study, it is demonstrated that the giant self-biased magnetoelectric (SME) response can be achieved from a center-clamped magnetostrictive–piezoelectric laminate composite by employing magnetic tip masses. An asymmetric laminate structure consisting of two different magnetostrictive layers (Metglas and nickel) with opposite signs of piezomagnetic coefficient is introduced to promote structural bending resonance, and the effect of layout change of attaching the magnetic tip masses on SME responses is systematically investigated. The highest SME effect is observed when all magnetic tip masses are loaded on the Metglas layer and their magnetization directions are normal to the Metglas surface. It is proposed that not only the parallel magnetic domains to external magnetic field but also the non-parallel magnetic domains effectively contribute to the total magnetostriction. The fabricated SME laminates exhibit giant SME voltage coefficients ranging from 14.11 to 52.35 V cm−1 Oe−1, depending on the direction of the fields of the tip magnets. These high SME voltage output values and their controllability are promising for precision field sensors, magnetic energy harvesters and field-tunable devices.

A Highly Efficient Self‐Biased Nickel‐Zinc Ferrite/Metglas/PZT Magnetoelectric Gyrator

A high efficiency self‐biased magnetoelectric (ME) gyrator operating under zero magnetic bias field (HBias = 0) was developed. It consists of a three‐phase nickel‐zinc ferrite/Metglas/piezoelectric longitudinal–transverse (L‐T) ME laminate and a solenoid. Laminates with different length–width (L/W) ratios, together with various thickness (number of Metglas foils) ratios between ferrite and Metglas layers, were studied. A maximum power conversion efficiency (η) of 72% was found at the fundamental electromechanical resonance for a high L/W ratio of 18.7. The high zero‐bias η could be attributed to a higher mechanical quality factor (Qm) and the low demagnetization effect (Nz) of nickel‐zinc ferrite laminates of higher L/W. Eliminating the external magnetic bias will facilitate miniaturization of ME gyrators for use in portable electronics and medical applications.

Evaluation of magnetomechanical conversion efficiencies in magnetoelectric gyrators

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.

Enhanced tunability of magneto-impedance and magneto-capacitance in annealed Metglas/PZT magnetoelectric composites

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.

Enhanced magnetoelectric effect in Metglas/K0.5 Na0.5NbO3/metglas lead-free ME laminates

We report the magnetoelectric (ME) coupling in lead-free ME composites composed of Metglas (2605SA1) and K[Formula: see text]Na[Formula: see text]NbO3 (KNN) phases. Thickness of the magnetostrictive layers ([Formula: see text] is changed by stacking number of Metglas layers ([Formula: see text]25[Formula: see text][Formula: see text]m for each layer) while KNN is maintained at a fixed thickness ([Formula: see text]300[Formula: see text][Formula: see text]m). As the number of Metglas layers increased, the peak magnitude of [Formula: see text] first increases, reaches a maximum and then decreases afterward. The static magnetic field ([Formula: see text], where [Formula: see text] shows maximum magnitude shift toward a higher value as number of layers increases. The maximum value of [Formula: see text] 91[Formula: see text]mVcm[Formula: see text]Oe[Formula: see text] is observed for optimized thickness ratio of [Formula: see text]/[Formula: see text] 1 (i.e. [Formula: see text] 5 layers) at [Formula: see text] 160[Formula: see text]Oe. The [Formula: see text] is further enhanced by taking advantage of magnetic flux concentration effect of Metglas as a function of its sheet aspect ratio. The present composites can offer promising opportunities of engineering environmental friendly ME laminate for applications in ME devices such as energy harvester and magnetic field sensors.

Magnetoelectric Coupling in Metglas/BaTiO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;/Metglas Lead-Free Magnetoelectric Composites

We report the magnetoelectric (ME) coupling in ME composites composed of NiFe2O4 (NFO) or metglas as magnetostrictive phases and BaTiO3 (BTO) as piezoelectric phase, targeting lead free magetnic field sensors. NFO and BTO phases were synthesized by solid state sintering method and further characterized by using XRD and FESEM techniques. The P-E hysteresis curve shows good ferroelectric behavior with saturation polarization of Ps = 15.87 C/cm2 and coercive electric field of 130 kV/cm. The ME response was characterized as a function of dc magnetic field at a fixed frequency. The transverse ME voltage coefficient, αME31 shows 2 times larger magnitude than that of longitudinal ME voltage coefficient, αME31. The maximum αME31 of 37 mV/cm•Oe (@Hdc = 250 Oe) is observed for NFO/BTO/NFO ME composites with thickness ratio of tm/tp = 1.0. The ME coupling is further enhanced by replacing NFO layers by highly magnetostrictive metglas layers. Metglas/BTO/metglas laminates show large αME31 value of 81 mV/cm•Oe at relatively lower Hdc of 145 Oe. The present laminates can offer promising opportunities of engineering environmental friendly ME laminate for applications in ME devices such as energy harvester and magnetic field sensors.

Temperature Characteristics of Magnetoelectric Effect in Bilayer Ferromagnetic-Piezoelectric Structures

Temperature characteristics of resonant magnetoelectric effect in bilayer structures consisting of langatate, lead zirconate titanate, nickel, and amorphous ferromagnetic Metglas layers have been investigated. The measurements were performed in the temperature range of 150-400 K. The influence of the ferromagnetic and piezoelectric layer’s parameters on the temperature dependence of resonant frequency and magnetoelectric coefficient αE has been demonstrated. The results can be used to develop magnetoelectric magnetic field sensors.

Influence of metglas layer on nonlinear magnetoelectric effect for magnetic field detection by frequency modulation

Linear magnetoelectric (ME) and nonlinear magnetoelectric effects are considered systematically in this paper. We have prepared 3 multi-push-pull magnetoelectric laminated composites Metglas/PMNT/Metglas with n layers metglas (n = 1, 2, and 3). When n increases from 1 to 3, the linear magnetoelectric charge coefficients increase from 1900 to 2200 and then to 2600 pC/Oe at 2 Hz under their each optimal magnetic bias. By using these 3 ME composites, we have also prepared 3 ME sensors, the sensitivity of which are as low as 130, 168, and 199 pT/√Hz at 1 Hz for n = 1, 2, and 3, respectively, via nonlinear modulation method. Therefore, the nonlinear ME charge coefficients decrease as layer numbers of metglas increase, which is different with the ME charge linear coefficient's increasing trend, also demonstrated coupled with the finite element analysis method. The factors that result in the higher nonlinear ME charge coefficient in ME composites with fewer metglas layers are analyzed and discussed in detail.

Voltage Tunable Magnetoelectric Inductors With Improved Operational Frequency and Quality Factor for Power Electronics

Inductors find widespread use in various applications. Inductors with a large tunability of inductance and quality factor would lead to new paradigm on circuit designs. In this paper, we investigated the effect of ferromagnetic layer thickness on the performance of a magnetoelectric tunable inductor. Using chemical etching, the thickness of Metglas ribbons (2605SA1) can be reduced from 24 to about 8 μm, which dramatically reduces the eddy-current loss at higher frequencies. With the same total thickness, compared with inductor constructed with unthinned Metglas layers (2605CO), the maximum quality factor can be increased for 80%, and the operational frequency range can be extended for 10× to the >10 MHz range. An inductance tunable range of L max /L min = 370% was also achieved together with a significantly enhanced quality factor by ~3. Furthermore, with an inductor constructed with single thin Metglas (2605HB1M) layer, the maximum quality factor can be increased by 150% with single PZT slab and by 235% with double PZT slabs, and the operational frequency range can be extended by 100× with single slab and by 200× with double slabs, which makes these metallic magnetic ribbons tunable inductors competitive with ferrite materials in adaptive inductive power supply systems.

High non-linear magnetoelectric coefficient in Metglas/PMN-PT laminate composites under zero direct current magnetic bias

The non-linear magnetoelectric (ME) response of Metglas/PMN-PT based sandwiched ME laminate composites has been studied for various thicknesses of the magnetostrictive layer. A significant increase in the non-linear ME coefficient under zero direct current bias was observed with a decreased Metglas thickness ratio for a fixed number of Metglas layers of n = 2. The non-linear ME effect was further improved by driving the laminate at the electromagnetic resonant frequency. The approach offers the potential to modulate low frequency magnetic signals to higher frequencies, where the noise floor is much lower and the signal to noise ratio higher.

A New Magnetoelectric Composite with Enhanced Magnetoelectric Coefficient and Lower Resonance Frequency

This study reports large magnetoelectric (ME) effect by attaching Ni and Metglas magnetostrictive layers to one free end of piezoelectric Pb(Zr,Ti)O3 (PZT) cantilever. By this structure, the influences of the bonding layer can be weakened so as to get relatively high ME voltage coefficient (αME) at resonance frequency. And the cantilever structural magnetostrictive material can supply stronger magnetic force to the PZT plate instead of the shear force in traditional structure, leading to an enhancement of αME at resonance frequency and generate a new resonance frequency of bending mode which is lower. Also, it can be used without bias field due to the built-in dc magnetic bias field between Ni and Metglas layers. Hence, it can obtain a larger αME at a lower resonance frequency at zero bias. The resonant αME at zero bias of the new composite reaches 50 V/cm∙Oe which is about 1.5~2 times as large as that of the traditional one. Besides, it greatly enhances the αME in a frequency range between two resonance frequencies. When we changed the length and thickness of Ni or Metglas layers, the results changed with them. Both the length and thickness have the optimum number to get a maximal αME. We also find if Ni and Metglas layers are not side to side aligned, αME at zero bias will decrease a lot.