Electromechanical Resonance Region Research Articles

Physics of Composites for Low-Frequency Magnetoelectric Devices.

The article discusses the physical foundations of the application of the linear magnetoelectric (ME) effect in composites for devices in the low-frequency range, including the electromechanical resonance (EMR) region. The main theoretical expressions for the ME voltage coefficients in the case of a symmetric and asymmetric composite structure in the quasi-static and resonant modes are given. The area of EMR considered here includes longitudinal, bending, longitudinal shear, and torsional modes. Explanations are given for finding the main resonant frequencies of the modes under study. Comparison of theory and experimental results for some composites is given.

Self-Biased Bidomain LiNbO3/Ni/Metglas Magnetoelectric Current Sensor.

The article is devoted to the theoretical and experimental study of a magnetoelectric (ME) current sensor based on a gradient structure. It is known that the use of gradient structures in magnetostrictive-piezoelectric composites makes it possible to create a self-biased structure by replacing an external magnetic field with an internal one, which significantly reduces the weight, power consumption and dimensions of the device. Current sensors based on a gradient bidomain structure LiNbO3 (LN)/Ni/Metglas with the following layer thicknesses: lithium niobate—500 μm, nickel—10 μm, Metglas—29 μm, operate on a linear section of the working characteristic and do not require the bias magnetic field. The main characteristics of a contactless ME current sensor: its current range measures up to 10 A, it has a sensitivity of 0.9 V/A, its current consumption is not more than 2.5 mA, and its linearity is maintained to an accuracy of 99.8%. Some additional advantages of a bidomain lithium niobate-based current sensor are the increased sensitivity of the device due to the use of the bending mode in the electromechanical resonance region and the absence of a lead component in the device.

Torsional modes in the magnetoelectric effect for a two-layer ferrimagnet-piezoelectric YIG / GaAs structure

The article is devoted to the theoretical study of the magnetoelectric (ME) effect in the magnetostrictive-piezosemiconductor structure of yttrium iron garnet (YIG) - gallium arsenide (GaAs) in the torsional mode. Earlier, it was found that the ME effect significantly increases with the transition from the low-frequency range to the region of electromechanical resonance (EMR). There are known results on the study of the ME effect in the range of different EMR modes: planar, flexural, and shear. This article proposes to consider the ME effect in the torsional mode region in a layered YIG-GaAs composite. Interest in this phenomenon is associated both with the study of the newest effect, and with the possibility of studying the ME effect in the region of magnetoacoustic resonance, i.e. when the torsional mode coincides with the spin wave in the region of ferromagnetic resonance. The results obtained can find application in the design of new ME devices.

Field dependence of magnetoelectric effect in the electromechanical resonance region on the Permendur -Quartz - Permendur structures

The results of an experimental study of the field dependences of the magnetoelectric effect on three-layer Permendur-Quartz-Permendur structures in the region of electromechanical resonance are presented. It has been established that at the electromechanical resonance there exists a bias magnetic field region in that an anomalous behavior of the field dependence of the magnetoelectric coefficient are observed. This effect is explained due to the presence of the AE effect in the magnetostrictive material.

Magnetoelectric Multilayer Gallium Arsenide–Nickel–Tin–Nickel Structures

The production process is considered, and the results of a theoretical and experimental study of the magnetoelectric effect in a multilayer structure obtained by galvanic deposition of alternating layers of nickel and tin onto a gallium arsenide substrate are presented. It is experimentally found that the use of tin as an intermediate layer in a multilayer structure decreases the mechanical stresses arising from the inconsistency of the lattice parameters at the nickel/gallium arsenide interface, which makes it possible to obtain high-quality multilayer structures with the thickness of the nickel layer of about 100 μm. On the basis of the joint solution of the equations of elastodynamics and electrostatics for the magnetostriction, piezoelectric, and buffer layers, an expression for the magnetoelectric voltage coefficient is obtained. It is theoretically shown and experimentally confirmed that the frequency dependence of the magnetoelectric coefficient has a resonant character, and the value of the resonant frequency gradually decreases with the growth in the number of layers from the value corresponding to the natural oscillation frequency of a plate made of gallium arsenide, approaching the value corresponding to the natural oscillation frequency of a plate consisting of a layer of nickel and tin, the thickness of which is equal to double the thickness of the layer of nickel. It is experimentally found that, in the region of electromechanical resonance, the obtained structures have a high quality factor Q ≅ 1000, which is more than 20-fold higher than the quality factor of the magnetoelectric structures fabricated by gluing, and have good adhesion between the layers. These structures are promising for creating devices based on the magnetoelectric effect.

Specific Features of the Magnetoelectric Effect in Permendur–Quartz–Permendur Structures in the Region of Electromechanical Resonance

The experimental frequency and field dependences of the magnetoelectric effect in three-layer permendur–quartz–permendur structures in the region of electromechanical resonance were studied. It was found that the magnetoelectric voltage coefficient and the Q-factor of these structures in the resonance region are much higher than those of similar structures based on lead zirconate titanate. Anomalous behavior of the field dependences of the magnetoelectric voltage coefficient and the Q-factor was observed in the region of electromechanical resonance. This feature is attributable to the negative ΔE effect.

Особенности магнитоэлектрического эффекта в структурах пермендюр-кварц-пермендюр в области электромеханического резонанса

AbstractThe experimental frequency and field dependences of the magnetoelectric effect in three-layer permendur–quartz–permendur structures in the region of electromechanical resonance were studied. It was found that the magnetoelectric voltage coefficient and the Q-factor of these structures in the resonance region are much higher than those of similar structures based on lead zirconate titanate. Anomalous behavior of the field dependences of the magnetoelectric voltage coefficient and the Q-factor was observed in the region of electromechanical resonance. This feature is attributable to the negative Δ E effect.

Technology of production and magnetoelectric characteristics of multilayer structures nickel-tin on the gallium arsenide substrate

The technology of fabrication and the results of the magnetoelectric effect investigation in sandwich structure manufactured by galvanic deposition tin and nickel on the gallium arsenide substrate are presented. It is shown that the use of tin as an intermediate layer lead to reduces the mechanical stresses resulting on the interface nickel and gallium arsenide. It is possible to obtain qualitative structures with nickel layer thickness on the order of 100 microns. Experimental results of the frequency dependence of the magnetoelectric voltage coefficient in the region of electromechanical resonance are presented. The resonance value of the magnetoelectric voltage coefficient reached 40V/(cm·Oe) with the Q-factor ≌ 700, which significantly exceeds the characteristics of similar structures obtained by bonding.

High-Q Magnetoelectric Nickel–Quartz–Nickel Structures

The results of experimental examination of the magnetoelectric parameters of three-layer nickel–quartz–nickel structures in the region of electromechanical resonance are presented. The structures have been fabricated by electrolytic deposition of nickel onto a quartz substrate. It has been found that their Q-factor in the region of electromechanical resonance is Q = 10000, which is considerably higher than the Q-factors of magnetoelectric structures fabricated earlier. The experimental data agree well with the earlier-presented theory.

Influence of the ΔE Effect on the Field Dependence of the Magnetoelectric Effect in the Region of Electromechanical Resonance

The influence of the ΔE effect on the field dependence of the resonant magnetoelectric effect in bulk composite materials with a composition of ferrite nickel spinel–lead zirconate titanate has been investigated in the electromechanical resonance region. It has been shown that the field dependence of the effect is determined not only by the magnetic-field dependence of the piezomagnetic coefficient, but also by the field dependence of the Young modulus. The dependence of the resonance frequency of the effect on the bias field has been analyzed.

Высокодобротные магнитоэлектрические структуры никель-кварц-никель

AbstractThe results of experimental examination of the magnetoelectric parameters of three-layer nickel–quartz–nickel structures in the region of electromechanical resonance are presented. The structures have been fabricated by electrolytic deposition of nickel onto a quartz substrate. It has been found that their Q-factor in the region of electromechanical resonance is Q = 10000, which is considerably higher than the Q-factors of magnetoelectric structures fabricated earlier. The experimental data agree well with the earlier-presented theory.

Predicting Magnetoelectric Coupling in Layered and Graded Composites.

Magnetoelectric (ME) interaction in magnetostrictive-piezoelectric multiferroic structures consists in inducing the electric field across the structure in an applied magnetic field and is a product property of magnetostriction and piezoelectricity in components. ME voltage coefficient that is the ratio of induced electric field to applied magnetic field is the key parameter of ME coupling strength. It has been known that the ME coupling strength is dictated by the product of the piezoelectric and piezomagnetic coefficients of initial phases. As a result, using the laminates with graded piezoelectric and piezomagnetic parameters are a new pathway to the increase in the ME coupling strength. Recently developed models predict stronger ME interactions in composites based on graded components compared to homogeneous ones. We discuss predicting the ME coupling strength for layered structures of homogeneous and compositionally graded magnetostrictive and piezoelectric components based on the graphs of ME voltage coefficients against composite parameters. For obtaining the graphs, we developed equations for ME output in applied magnetic field for possible modes of operation and layered structure configurations. In particular, our studies have been performed on low-frequency ME coupling, enhanced ME effect in electromechanical resonance (EMR) region for longitudinal and bending modes. Additionally, ME coupling at magnetic resonance in magnetostrictive component and at overlapping the EMR and magnetic resonance is investigated. We considered symmetric trilayers and asymmetric bilayers of magnetostrictive and piezoelectric components and multilayered structures based on compositionally stepped initial components.

Magnetoelectric effect in layered disk-shaped magnetostrictive–piezoelectric structures: Theory and experiment

Theoretical and experimental studies of the magnetoelectric effect in a disk-shaped magnetostrictive–piezoelectric structure in the electromechanical resonance region are presented. An expression for the magnetoelectric voltage coefficient is derived based on the simultaneous solution of elastodynamic and electrostatic equations separately for magnetostrictive and piezoelectric layers. The conditions at the interface were taken into account based on the premise that the interaction between layers is implemented by shear. It is shown that the inhomogeneity of the voltage and strain distribution over the sample thickness, caused by the interface, leads to a significant contribution to the effect in the case of thick layers. The theoretical and experimental dependences of the frequency characteristic of the effect are presented for the permendur–lead zirconate-titanate–permendur structure. The theoretical calculations are in good agreement with experimental data.

Magnetoelectric Effect in Ferrite-Piezoelectric Dual-Phase Structure

This manuscript is devoted to the magnetoelectric coupling in a dimensionally graded magnetostrictive-piezoelectric structure in the electromechanical resonance region. Theoretical frequency dependence of ME voltage coefficient is obtained. Theoretical estimates for the layered structure of lead zirconate-titanate and single-crystal Zn0,3Ni0,7Fe2O4 are in satisfactory agreement with data. The obtained results are expected to facilitate observation of enhanced ME coupling at overlapping of electromechanical and magnetic resonance due to energy transfer between spin waves and phonons.

Magnetic Field Tunable Electromechanical Resonance Properties of Magnetoelectric Bilayer

The present paper focuses on the magnetoelectric coupling in dimensionally graded ferrite-piezoelectric bilayers in the electromechanical resonance region. Using the bilayer as a transducer which converts the ac magnetic field into an ac electric field shows that the transmission coefficient equals approximately -83 dB for zero bias magnetic field and -44 dB for bias field of 340 Oe. Thus, applying the DC field enables one to obtain the transmission coefficient variation range of 39 dB for the investigated structure. The phenomenon is of importance for the realization of multifunctional magnetoelectric devices including sensors and transducers operating at microwave frequencies.

The influence of the adhesive bonding on the magnetoelectric effect in bilayer magnetostrictive-piezoelectric structure

The influence of the interlayer adhesive bonding is considered in bilayer magnetostrictive-piezoelectric structure. The expression for the frequency dependence of the magnetoelectric voltage coefficient in the electromechanical resonance region is obtained using the simultaneous solution of the motion equations for the magnetostrict- ive, adhesive, piezoelectric phases and material equations. It is shown that in the passage to the limits this expression for the coefficient transforms to the expression for ideal connection between the layers.

The magnetoelectric effect in structures based on metallized gallium arsenide substrates

The magnetoelectric effect in the electromechanical resonance region is studied experimentally for the first time in structures in the form of gallium arsenide substrates with their two sides metallized with thin nickel or cobalt films and gold films (Ni-GaAs-Au and Co-GaAs-Au). The dependence of the magnetoelectric effect on the magnetization field in a Ni-GaAs-Au structure has an anomalous shape that is uncharacteristic of known composite magnetoelectric materials based on ceramic piezoelectrics. The maximum magnetoelectric coefficient under resonance is 81.2 V/A. This corresponds to the giant magnetoelectric effect at room temperature. It is shown that this resonance is characterized by a high Q-factor of up to 8000.

Uniformity of direct and converse magnetoelectric effects in magnetostrictive–piezoelectric composites

In this paper, we theoretically and experimentally confirmed the uniformity of magnetoelectric (ME) coupling coefficients for the direct and converse ME (DME and CME) effects in longitudinal-transverse (L-T) mode magnetostrictive–piezoelectric two-phase composites, both at low frequencies and in the electromechanical resonance region. We also discussed the flaws in previous measurements of the ME coupling coefficients, which led to misunderstandings in the uniformity between the DME and CME effects. Our current work provided a correct method to correctly understand ME coupling in magnetostrictive-piezoelectric two-phase composites.

Nonlinear magnetoelectric effect in composite multiferroics

The theoretical and experimental studies of the nonlinear magnetoelectric effect in composite multiferroics in the low-frequency spectral region and in the electromechanical resonance region have been performed. It has been shown that such structures demonstrate a nonlinear magnetoelectric effect, which is quadratic in ac magnetic field strength at weak magnetic fields. In the region of the electromechanical resonance, the resonance excitation of an electric field occurs by means of ac magnetic field at a frequency lower than the resonance frequency by a factor of two. In the low-frequency spectral region, there is a difference of amplitude values of two neighboring voltage maxima due to the superposition of signals from the linear and nonlinear effects, and the difference is proportional to the dc magnetic field strength in weak fields. The results of the experimental study of the two-layer permendur-lead zirconate titanate structure are presented.

Influence of an interlayer bonding on the magnetoelectric effect in the layered magnetostrictive-piezoelectric structure

The theory of the magnetoelectric effect in magnetostrictive-piezoelectric bilayer structure is presented considering the interlayer bonding material. The expressions for the dispersion relation and the frequency dependence of the magnetoelectric voltage coefficient in the electromechanical resonance region are obtained, using the simultaneous solution of the motion equation and material equations taking into account the interlayer bonding phase. The theoretical and experimental dependence of the magnetoelectric effect on the thickness of the bonding material layer are presented. Results are in good agreement with the theory and experiment.