Vladimir Petrov

Modeling of Magnetoelectric Effect in Ferromagnetic/Piezoelectric Multilayer Composites

A theoretical model is presented for of magnetoelectric effect in bilayer and multilayer composites. A novel approach to take into account the actual boundary conditions in multilayer composites is proposed. An averaging method is used for deriving effective material parameters in composites. The effect of dielectric and magnetic parameters on the magnetoelectric susceptibility is studied. The estimated magnetoelectric coupling constants are compared with data for nickel ferrite and lead zirconate titanate composite.

Magnetoelectric Interactions in Lead-Based and Lead-Free Composites

Magnetoelectric (ME) composites that simultaneously exhibit ferroelectricity and ferromagnetism have recently gained significant attention as evident by the increasing number of publications. These research activities are direct results of the fact that multiferroic magnetoelectrics offer significant technological promise for multiple devices. Appropriate choice of phases with co-firing capability, magnetostriction and piezoelectric coefficient, such as Ni-PZT and NZFO-PZT, has resulted in fabrication of prototype components that promise transition. In this manuscript, we report the properties of Ni-PZT and NZFO-PZT composites in terms of ME voltage coefficients as a function of frequency and magnetic DC bias. In order to overcome the problem of toxicity of lead, we have conducted experiments with Pb-free piezoelectric compositions. Results are presented on the magnetoelectric performance of Ni-NKN, Ni-NBTBT and NZFO-NKN, NZFO-NBTBT systems illustrating their importance as an environmentally friendly alternative.

Magnetoelectric effect at thickness shear mode in ferrite-piezoelectric bilayer

This manuscript discusses first observation of magnetoelectric (ME) coupling at thickness shear modes in a magnetostrictive-piezoelectric bilayer. The measured value of magnetoelectric voltage coefficient is optimized by adjusting the geometry of layers. Theoretical estimates for the bilayer of Y-cut langatate and yttrium iron garnet 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.

Magnetoelectric Sensor of Magnetic Field

As an alternative to semiconductor sensor and sensor on hermetic contacts we present sensor based on magnetoelectric effect. In researches there are used the magnetoelectric bulk composites containing 95% of yttrium-iron garnet and 5% of lead zirconate titanate (PZT) and multilayer composite material consisting of PZT and Ni 0.5 Zn 0.5 Fe 2 O 4 . The magnetoelectric sensor represents the disk or plate from the magnetoelectric material with two electrodes for connecting to the voltage meter. The action of the sensor is based on magnetoelectric interaction. The experimental model was made for determining the basic parameters of the magnetoelectric sensor and optimization of its design.

Composite magnetoelectrics: Their microwave properties

Abstract The influence of the external electric field upon the main line of the ferromagnetic resonance spectrum in the composite ferrite-ferroelectric materials at the basis of yttrium-iron garnet and piezoelectric ceramics of PZT type has been investigated. The phenomenological theory of the magneto-electric effect in the investigated materials has been developed. The magneto-electric constants for the composition of 90% of yttrium-iron garnet and 10% PZT-ceramics have been determined. The comparison of the experimental data and the calculation on the striction model of the interaction of the ferroelectric and ferrite phases is given.

Modeling of Magnetoelectric Effects in Composites

This book brings together numerous contributions to the field of magnetoelectric (ME) composites that have been reported so far. Theoretical models of ME coupling in composites relate to the wide frequency range: from low-frequency to microwave ones and are based on simultaneous solving the elastostatic/elastodynamic and electrodynamics equations. Suggested models enable one to optimize magnetoelectric parameters of a composite. The authors hope to provide some assimilation of facts into establish knowledge for readers new to the field, so that the potential of the field can be made transparent to new generations of talent to advance the subject matter.

Tunable magnetoelectric response of dimensionally gradient laminate composites

A magnetoelectric (ME) sensor exhibiting wideband behavior as a function of applied magnetic DC bias and frequency was designed by combining the dimensionally gradient piezoelectric layer with Metglas magnetostrictive layers in laminate configuration. The ME coefficient of the band in the DC magnetic range of 52–242 Oe was measured to be 3000 mV/cm Oe under the resonant condition of f = 107 kHz. The wideband in the AC magnetic field frequency range of 41–110 kHz had the ME coefficient in the vicinity of 260 mV/cm Oe under the conditions of HAC = 1 Oe and HDC = 70 Oe. This frequency-dependent ME behavior clearly showed two different states on each side of the resonance peak which could open the possibility of developing new applications such as magnetic field-controlled switches.

Magnetoelectric Microwave Devices

Design of microwave devices on the base of magnetoelectric materials is one of the advanced directions of the solid-state microelectronics development. In our researches there were used bulk and multilayer composites. This paper is devoted to studying the controlling magnetoelectric devices. Characteristics of resonance magnetoelectric attenuator were measured at microwave region.

Electromechanical Resonance in Magnetoelectric Composites: Direct and Inverse Effect

Magnetoelectric (ME) coupling in the composites is mediated by the mechanical stress and one would expect orders of magnitude stronger coupling when the frequency of the ac field is tuned to acoustic mode frequencies in the sample than at non-resonance frequencies. A model is presented for the increase in ME coupling in magnetostrictive-piezoelectric bilayers for the longitudinal, radial, and bending modes in the electromechanical resonance region. We solved the equation of medium motion taking into account the magnetostatic and elastostatic equations, constitutive equations, Hookes law, and boundary conditions. We estimated the ME voltage coefficient for direct ME effect and ME susceptibility for inverse ME coupling. The frequency dependence of the ME voltage coefficient and ME susceptibility reveals a resonance character in the electromechanical resonance region. Then we considered ME interaction in the magneto-acoustic resonance region at the coincidence of electromechanical and magnetic resonance. Variation in the piezomagnetic coefficient with static magnetic field for magnetic layer results in a dependence of ME voltage on applied bias magnetic field. As an example, we considered specific cases of cobalt ferrite or yttrium-ferrum garnet - lead zirconate titanate and nickel/permendur - lead zirconate titanate bilayers. Estimated values of ME voltage coefficient versus frequency profiles are in agreement with data.

Resonance magnetoelectric effect in multilayer composites

The phenomenological theory is presented on the influence of external electric field on the shift of resonance magnetic field, magnetic and magnetoelectric (ME) susceptibilities of composites. The shift of resonance magnetic field is proportional to linear and bilinear ME constants. The concentration and electric field dependencies of magnetic resonance field shift for layered nickel ferrite, lithium ferrite and yttrium iron garnet with ferroelectric lead zirconate titanate are calculated. Three measurement methods of ME susceptibility using resonant ME connection, electrical dipole transitions and resonant ME effect are proposed. The method of electrical dipole transitions is investigated in detail. Expressions for linear and bilinear ME susceptibility of the composite (symmetry point group 3 m or 4 mm) at high frequencies are found. The results of ME susceptibility measurement are useful for the analysis of electrically controlled high frequency devices of magnetic type, such as phase shifters, attenuators, and filters.