Magnetomechanical Resonance Research Articles

High-Sensitivity Wireless Sensing Using Amorphous Magnetic Microwires

Glass-coated amorphous ferromagnetic microwires subjected to variations in mass loading and parallel wire arrays with 0.5–6-cm interwire spacing were found to deliver exceptional magnetomechanical and wireless giant magnetoimpedance (GMI) responses, in the kilohertz and microwave range, respectively. The microwires allow wireless quantification of microgram mass differences: the magnetomechanical resonance frequency measured in zero applied field demonstrates an approximately linear decrease of 3 Hz/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{g}$ </tex-math></inline-formula> , and a sensitivity response that is ten times greater than that reported for commercial METGLAS-type amorphous magnetic ribbons of comparable length. Microwave giant magnetoimpedance data collected from planar arrays of parallel microwires show either constructive or destructive interference when compared to data obtained from a single microwire. The exceptional responsiveness of the glass-coated amorphous ferromagnetic microwires to mass loading and to geometric arrangement, along with their small diameter and ease of fabrication, highlights their promise for a wide variety of sensor applications, including biosensing, civil infrastructure monitoring, and high-throughput remote detection schemes.

Low-Frequency Dual-Driven Magnetoelectric Antennas With Enhanced Transmission Efficiency and Broad Bandwidth

Low frequency (LF) dual-driven magnetoelectric (i.e., DDME) antennas are proposed, which include a pair of self-biased magnetoelectric (ME) heterostructures (i.e., Ni/Metglas/ [Pb(Zr,Ti)O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> /Metglas/Ni) wrapped with small coils. For the DDME transmitter, the [Pb(Zr,Ti)O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> layers are designed as a piezoelectric transformer. This enhances the transmitted magnetic field significantly due to the dual-driven mode: the generated magnetic field of transmitting coils driven by the transformer at the magneto-mechanical resonance (MMR) and magnetization oscillation of magnetostrictive layer driven by the mechanical stress of inverse piezoelectric effect. Meanwhile, the DDME receiver consists of a self-biased ME heterostructure wrapped with search coils, whose signal-to-noise ratio (SNR) is improved due to the synergistically induced voltage of Faraday law's induction and ME effects. The nonmonotonic inductance of search coils near MMR broadens the bandwidth (1904 kHz) due to the LC resonances at multiple frequencies. The letter indicates that the DDME antenna achieves a communication distance of 11 m with power consumption of 212.7 mW, whose operation distance and channel capacity (12.54 kbit/s) are 1.69 times and 10.62 times larger than that of ME antenna (i.e., Ni/Metglas/[Pb(Zr,Ti)O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> /Metglas/Ni). The communication distance can be further increased to 170 m with a larger DDME antenna. Furthermore, the DDME antenna can realize more robust ASK modulation compared to ME antenna.

Measurement of Birefringence Using the Magneto-Optical Modulator in the Magnetomechanical Resonance Mode

In order to detect magnetic linear birefringence of new materials, we have developed an installation using the magneto-optical modulator in the mode of magnetomechanical resonance. We have theoretically substantiated and experimentally applied radiation with phase-frequency dependencies of the Stokes vector on magnetomechanical resonance frequency for measuring magnetic linear birefringence. Our results demonstrate that the radiation in which the variable components of the Stokes vector have different initial phases after passing through the sample with linear birefringence leads to additional phase delays of the signal at the output of the photopolarimeter. As an example, the results of measurements of the magnetic linear birefringence in the film of yttrium iron garnet have been introduced. The minimum value of the linear birefringence which was measured in this experiment 0.018 deg. The advantage of the installation is the independence of the measurements results from the changes of the intensity in the optical system.

Energy harvesting device based on a metallic glass/PVDF magnetoelectric laminated composite

A flexible, low-cost energy-harvesting device based on the magnetoelectric (ME) effect was designed using Fe64Co17Si7B12 as amorphous magnetostrictive ribbons and polyvinylidene fluoride (PVDF) as the piezoelectric element. A 3 cm-long sandwich-type laminated composite was fabricated by gluing the ribbons to the PVDF with an epoxy resin. A voltage multiplier circuit was designed to produce enough voltage to charge a battery. The power output and power density obtained were 6.4 μW and 1.5 mW cm−3, respectively, at optimum load resistance and measured at the magnetomechanical resonance of the laminate. The effect of the length of the ME laminate on power output was also studied: the power output exhibited decays proportionally with the length of the ME laminate. Nevertheless, good performance was obtained for a 0.5 cm-long device working at 337 KHz within the low radio frequency (LRF) range.

Peculiarities of the modulation of optical radiation during magnetomechanical oscillations in bilayer composite structures

Peculiarities of the modulation of optical radiation during the excitation of magnetomechanical oscillations in a composite structure consisting of magneto-optical crystal and magneto-passive layer have been studied. Analytical expressions for the amplitude- and phase-frequency characteristics of a magneto-optical light modulator based on the Faraday effect for a low-frequency mode under conditions of magnetomechanical resonance were obtained. The results of theoretical and experimental investigations of a modulator in the form of bilayer composite structure consisting of yttrium iron garnet and quartz glass were presented. The relative change of the amplitude of polarization plane rotation in the region of resonance frequencies at the level of 25% and the phase delay of 22° were obtained experimentally.

The possibility of measuring linear and quadratic magnetooptical effects in magnetic field under conditions of magnetomechanical resonance

We have considered the possibility of measuring the linear and quadratic (in magnetic field) magnetooptical effects in magnetooptical crystals that are simultaneously exposed to a constant (polarizing) magnetic field and to an alternating magnetic field under conditions of magnetomechanical resonance. The use of a Mueller polarimeter in combination with spectral analysis of the intensity of the light wave at the output of the polarimeter makes it possible to selectively determine elements of the Mueller matrix and minimize the amount of measurements. We have shown that there is a possibility of solving the inverse problem on finding two components of the alternating magnetic field in which a magnetooptical crystal is placed.

Effect of sizes and polarizing magnetic field on the values of material constants of ferrimagnets in magnetomechanical resonance conditions

A mathematical model of magnetomechanical compression-extension oscillations of a ferrimagnet having the shape of a right parallelepiped in a polarizing magnetic field is constructed. The solution to the equation derived here makes it possible to determine the resonance frequencies of oscillations for various relations between the length and the cross section of the sample and for various values of the polarizing magnetic field. The results of computations for an yttrium ferrite-garnet sample are compared with the results of measurements. The experimental value of the elastic tensor component for yttrium ferrite-garnet is obtained.

Depolarization of light in magnetooptical crystals under magnetomechanical resonance conditions

Taking into account multiple reflections inside a magnetooptical crystal under conditions of magnetomechanical resonance, we determine the change of polarization degree of light passing through the sample using methods of Muller matrices and of the Stokes vector.

Colossal magnetoelectric response of PZT thick films on Ni substrates with a conductive LaNiO3 electrode

We have characterized the magnetoelectric (ME) properties of Pb(ZrTi)O3/LaNiO3/Ni (PZT/LNO/Ni) composites, which are fabricated using aerosol deposition. LNO acted as the bottom electrode for the PZT film and could effectively transfer the stress generated through the magnetostrictive effect of Ni into the piezoelectric PZT film. The PZT/LNO/Ni ME structure exhibits an ME coefficient αE31 = 1 V cm−1 Oe−1 at a very low bias magnetic field of 30 Oe and shows 8.5 V cm−1 Oe−1 at a magneto-mechanical resonance frequency of 204 kHz corresponding to the Ni substrate. These huge ME coefficients are attributed to the improved coupling between the magnetostrictive Ni layer and the piezoelectric PZT thick film via the LNO layer, which is possible due to similar mechanical impedances of Ni, LNO and PZT.

Features of the stokes vector of polarized radiation when passing through a magneto-optical crystal under conditions of magnetomechanical resonance

Components of the Stokes vector are shown to undergo amplitude- and phase-frequency variations for a magneto-optical thin rod-shaped crystal located under conditions of magnetomechanical resonance when the variable magnetic field is directed at an acute angle to the light propagation axis coinciding with the crystal oscillation axis. It is noted that the phase relations for these components must be taken into account for polarized light when finding the connection between the variable and constant components of the Stokes vector.

The effect of magnetomechanical resonance on light polarization in magneto-optical crystals

The peculiarities of changes in the polarization of light passing through a crystal have been investigated for the case of magnetomechanical resonance within the model of longitudinal oscillations of a magneto-optical crystal shaped as a thin rod. The geometry of the magnetic fields is chosen so as to bring about a change in the light polarization by the Faraday and Cotton-Mouton effects. The amplitude and phase-frequency dependences of the variable components of the Faraday effect and the elements of the Stokes vector are plotted in the range of resonant frequencies of longitudinal oscillations of magnetomechanical crystal using the example of yttrium ferrite garnet.

Magneto-mechanical resonance of a single superparamagnetic microbead trapped by a magnetic domain wall

Magnetic domain walls in ferromagnetic tracks can be used to trap and transport superparamagnetic beads for lab-on-a-chip applications. Here it is shown that the magnetostatic binding between a domain wall and a superparamagnetic bead suspended in a host fluid leads to a distinct magneto-mechanical resonance under application of a sinusoidal driving field. The characteristic resonant frequency depends on the ratio of the magnetostatic binding force to the viscous drag on the bead. This resonance has been experimentally detected for a single trapped superparamagnetic bead using an optical detection technique.

Integrated capture, transport, and magneto-mechanical resonant sensing of superparamagnetic microbeads using magnetic domain walls

An integrated platform for the capture, transport, and detection of individual superparamagnetic microbeads is described for lab-on-a-chip biomedical applications. Magnetic domain walls in magnetic tracks have previously been shown to be capable of capturing and transporting individual beads through a fluid at high speeds. Here it is shown that the strong magnetostatic interaction between a bead and a domain wall leads to a distinct magneto-mechanical resonance that reflects the susceptibility and hydrodynamic size of the trapped bead. Numerical and analytical modeling is used to quantitatively explain this resonance, and the magneto-mechanical resonant response under sinusoidal drive is experimentally characterized both optically and electrically. The observed bead resonance presents a new mechanism for microbead sensing and metrology. The dual functionality of domain walls as both bead carriers and sensors is a promising platform for the development of lab-on-a-bead technologies.

The Impact of Vibration Due to Magnetostriction on the Core Losses of Ferrite Toroidals Under DC Bias

The ferrite cores of transformers and inductors are commonly excited under dc bias conditions in power electronic circuitry. Results have previously been presented showing core losses increase significantly with dc bias, along with various explanations for the cause. This paper presents measurements showing a strong correlation between core losses, and the magnetostrictive vibration caused by the presence of a dc bias. The measurements are made on power grade material ferrite toroidal cores at frequencies equal to, and distant from magnetomechanical resonance. Based on this evidence it is proposed that a mechanism causing core losses to increase with dc bias is the increase in vibration with dc bias, with losses being dependent on the amplitude and nature of the vibration waveform. The means by which core losses increase with vibration are also described.

Dynamic parameters of Tb-Dy-Fe giant magnetostrictive alloy

Tb 0.3Dy 0.7Fe 1.90 <110> oriented rods were prepared by zone melting with unidirectional solidification. The magnetomechanical coupling factor ( k 33) was measured by magnetomechanical resonance under different DC bias fields up to 77.4 mT. An effective method was provided to calculate sonic velocity, elastic modulus and compliance constant through measuring resonate frequency ( f r ), and calculate dynamic magnetostriction( d 33) via measuring magnetic permeability, magnetomechanical coupling factor( k 33) and compliance constant. Without pre-stress, resonate frequency ( f r ), sonic velocity and elastic modulus first decreased and then rose with increasing bias magnetic field. Under 10 MPa pre-stress, resonate frequency ( f r ), sonic velocity and elastic modulus decreased linearly with increasing bias fields. d 33 exhibited the same variation trend before and after heat treatment, but heat treatment weakened the decrease of d 33 in low field range.

Unusual Effects Measured Under DC Bias Conditions on MnZn Ferrite Material

Switch mode power supplies are the predominant form through which power conversion is currently implemented in electronic equipment. Within such power supplies, ferrite cored magnetic components are commonly placed under dc bias conditions which, due to magnetomechanical effects, can result in higher than expected core losses. This paper presents measurements that show the impact of magnetomechanical effects on the losses of a MnZn ferrite core material under low ac excitation and high dc bias conditions. The measurements are made using an accurate measurement circuit, and the results show the impact on losses of magnetomechanical resonance. In addition distorted, figure-eight shaped <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> loops are measured, which are also believed to manifest from magnetomechanical interactions. These <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> loops show that, on a transient basis, magnetomechanical interactions may take place in a manner that is not only lossless, but returns energy back to the excitation supply.

Magneto-Mechanical Resonance in a Model 3-Phase 3-Limb Transformer Core Under Sinusoidal and PWM Voltage Excitation

This investigation presents the measurement results of acoustic noise and vibration of a model three-phase three-limb transformer core under sinusoidal and PWM voltage excitation for assigned value of modulation index with switching frequency from 1 kHz to 3 kHz at no-load condition. Results show that the acoustic noise decreased around 2 (dBA) with increasing switching frequency. However, magneto-mechanical resonance phenomenon was observed at 3 kHz vibration frequency, which could cause excess acoustic noise under some excited conditions.

Magnetoelectric resonant characteristics in Pb(Zr,Ti)O3/Terfenol-D laminate composites

Magnetoelectric (ME) characteristics in a simple Pb(Zr,Ti)O3/Terfenol-D laminate composite are investigated. Both magnetomechanical and electromechanical resonances (EMRs) can enhance ME coupling and the latter plays a more important role. The phase spectra show a significant phase shift of 0.75π–π around each EMR frequency and a clear phase bouncing around each magnetomechanical resonance frequency. The distributions of the electric-field-induced magnetization (EIM) express different manners in longitudinal and transverse directions, which are attributed to the magnetized directions and the resonant modes. When the driving electric field frequency is near one of the integer EMR frequencies, multiple resonance EIMs are observed.

Longitudinally driven giant magneto-impedance effect enhancement by magneto-mechanical resonance

Longitudinally driven giant magneto-impedance (GMI) effect in amorphous magnetostrictive Fe 24Co 11.82Ni 47.3Si 1.47B 15 ribbons was investigated. The experimental results showed that the magneto-mechanical resonance of the ribbons had significantly enhanced GMI effect. The strong magneto-mechanical coupling (MMC) interaction resulted in high MI ratio. Maximal GMI ratio of 1532% was obtained in the sample annealed at 340 °C under transverse magnetic field. The results are explained in terms of MMC and resonance of the magnetostrictive materials.

Resonance magnetoelectric effect in bulk composites of lead zirconate titanate and nickel ferrite

Magnetoelectric (ME) Pb(Zr0.52Ti0.48)O3 (PZT)–NiFe2O4 bulk composites with various PZT volume fractions were prepared. The ME coupling coefficient, impedance, and flux density versus the frequency were measured. The magnetic bias and PZT volume fraction in the composites are investigated to optimize the ME output. It is revealed that ME resonances are caused by electromechanical resonance in the piezoelectric phase and magnetomechanical resonance in the magnetostrictive phase. Maximum magnetoelectric voltage coefficient resonance values of 6.7 V/cm Oe at 132.6 kHz and 6.12 V/cm Oe at 427.2 kHz for the composite with optimized PZT volume fraction of 0.55 were obtained at optimized magnetic bias of 0.6 kOe.