Magnetoelastic Properties Research Articles

On the Origin of Signal and Bandwidth of Converse Magnetoelectric Magnetic Field Sensors

AbstractConverse magnetoelectric sensors enable the detection of low‐frequency and low‐amplitude magnetic fields over a bandwidth of several kilohertz by combining the electrical excitation of a magnetoelectric resonator via a piezoelectric layer with an inductive readout. Here, a comprehensive sensor model is presented to further foster the development of this promising sensor concept. The model relates the output signal to the device characteristics, taking into account the magnetoelastic and electromechanical properties, the resonator geometry, and operating conditions. The sensor system is thoroughly experimentally analyzed to validate the model. Based on the analysis, the sensor concept is explained in detail, including the origin of its loss and bandwidth and their connection with the magneto‐mechanical loss in the magnetostrictive layer. Significant advances have been made in the comprehensive understanding of converse magnetoelectric sensors, providing a solid basis for future improvements in magnetoelectric sensor systems.

Structure, electronic and magneto-elastic properties of rare earth nitrides Ln3NIn (Ln = Nd, Pm, Sm, Eu, Gd, Tb) anti-perovskites

Electronic structure and magneto-elastic characteristics of lanthanide nitrides Ln3NIn (Ln = Nd-Tb) are explored by DFT. The structural reported data are reliable with the experimental outcomes and the observed structural characteristics drop from Nd to Tb due to the small atomic radii of Tb compare to Nd. Electrical resistivity and electronic characteristics demonstrate that all the investigated compounds are metallic. The resistivity at 300 K emphasizes that they are effective conductors. These compounds are ideal for situation where large acting load are expected such as implants that bear a disproportionate amount of weight as endoprostheses for hip, knee and as screw, nails and plates, especially when structural materials need to have sufficient bending fatigue strength for skeletal reconstruction. These compounds are antiferromagnetic and their Neel temperatures are 18, 15, 39, 45, 27, and 33 K, respectively. These compounds might be therefore feasible for magnetic cloaking and storage technologies.

Magnetic and magnetostrictive properties of Cu-doped cobalt ferrite

The Cu-doped cobalt ferrites CuxCo1-xFe2O4 (CCFO) were synthesized by a glycine-nitrate sol-gel auto-combustion method and investigated for structural, magnetic and magnetostrictive properties. X-ray diffraction and scanning electron microscopy analysis revealed the formation of single cubic-spinel phase for all the as-prepared powders, followed by the sintered samples with grain sizes around 2.5 µm. The variation in stoichiometric composition can be used to tailor magnetic and magnetostrictive properties. Saturation magnetization MS decreases from 84.8 to 60.4 emu/g with increasing Cu content from x = 0.0 to x = 0.50, accompanied with a reduction in coercivity HC from 1.21 to 0.41 kOe. The introduction Cu into CFO is conductive to the decline in magnetocrystalline anisotropy, giving rise to an improvement in magnetostriction at low applied fields. An optimized composition in the CuxCo1-xFe2O4 ferrites is found to be around x = 0.30, achieving good magnetoelastic properties, i.e., a large saturation magnetostriction (–λS ∼ 240 ppm), a high strain sensitivity (–dλ/dH ∼ 1.44 nm/A), as well as a low magnetocrystalline anisotropy coefficient (K1 ∼ 3.7 × 106 erg/cm3). The excellent magnetoelastic properties and the combination in a facile synthesis process for sintered polycrystalline ferrites, suggest promising prospects in magnetostriction applications.

Magnetoelastic coupling for Fe–Ga thin films epitaxially grown on different substrates

This paper reports the systematic study on the structure, magnetic properties and magnetoelastic properties for the Fe100−x Ga x (001) thin films epitaxially grown on the different substrates of GaAs(001) and MgO(001) using the sputtering technique. The alloy composition dependence of effective magnetoelastic coupling coefficient B eff along the FeGa [110] direction indicated that the largest magnetoelastic coupling was obtained for the Fe–Ga layer with x = 30 grown on the MgO substrate, which was evaluated to be B eff = − 9.4 × 107 erg cm−3. Considering the results of structural analysis and magnetization measurement, the different crystallite sizes depending on the kind of substrate may give rise to the different magnetoelastic coupling strengths between the Fe–Ga layers on the MgO and the GaAs. The magnetostriction along the Fe–Ga [111] direction λ 111 was also estimated with the assumption of plausible elastic property of Fe–Ga, and showed the values comparable to the reported value of bulk Fe–Ga. This means the large magnetostriction can be obtained even for the Fe–Ga thin films epitaxially grown not only on the GaAs(001) but also on the MgO(001). The findings in this work will give a guideline for designing spintronic applications with a Fe–Ga layer exhibiting a large magnetoelastic coupling.

Ударное возбуждение магнитоупругой системы периодической последовательностью сверхкоротких импульсов поля

The nonlinear magnetization precession in normal magnetized ferrite film which has magnetic, elastic and magnetoelastic properties is investigated. The excitation field is presented as a vibration on resonance frequency which is modulated by short pulses which frequency is more lower than resonance frequency. It is proposed the formation procedure of periodic succession of ultra-short pulses by the involution to even degree of modulation signal sine. It is found two different cases of excitation: first when modulate pulse duration is larger than initial signal period and second when modulate pulse duration is smaller than initial signal period. In the first case the modulated signal has the form of main frequency vibrations tandem and in the second case the modulated signal has the form of unit sign-variation pulse. It is investigated the time development of magnetic and elastic vibrations whish are firmed by excitation field. It is shown that in the first case the magnetization vibrations at first hat sharp jump to upward and after this decreases by exponent. In this case the elastic vibrations after the same jump at first increases and then decreases by exponent. The elastic vibrations behaviour is interpret as energy pump from magnetic system to elastic system. In the second case the initial jump both vibrations is absent. It is investigated the degree modulation index influence to excited vibrations. It is shown that by increasing of this index the amplitude of magnetic and elastic vibrations decreases. It is investigated the magnetization excited vibrations character by different degree of magnetoelastic connection. It is introduced the coefficient multiple of magnetoelastic constant which is equal to ratio of considered constant to value of magnetoelastic constant of yttrium iron garnet. It is shown that by increasing of multiple coefficient the magnetization vibrations period is increased. It is found the sharp increasing the period by determined value of multiple coefficient which has a threshold character. It is investigated the excitation of magnetization in large time interval when the multiple coefficient is above the threshold value. It is found the principle difference between two cases when pulse duration is large or smaller as alternating field period. It is shown that in the first case the magnetization vibrations has the character of equilibrium position precession in conditions of orientational transition. In the second case the magnetization vibrations has the form of periodic re-orientational jumps from one equilibrium position to another. It is mentioned some properties of observed phenomena and proposed some recommendations for further investigations.

Studying the magnetoelastic properties of a steel sheet under bending deformation

Studying the magnetoelastic properties of a steel sheet under bending deformation

Structural, micro-structure, magnetic and dynamic magneto-elastic properties of samarium-doped nickel-zinc spinel ferrites for efficient power conversion applications

Development of high-quality ferrites behaved enhanced properties via inclusion of ions in 3dn and 4fn series are desirable for efficient power conversion solid-state devices. Nevertheless, inadequate microscopic behaviors with complex chemistry in materials enables researchers to design and produce the macroscopic target device that remained rudimentary and mindless. In this work, the microscopic properties in nickel-zinc spinel ferrite series of Ni0.8Zn0.2SmxFe2-xO4 (x = 0, 0.02, 0.04, 0.06, 0.08) encompassing XRD, SEM, EDS, VSM, FTIR and ESR were systemically characterized, and the evolutionary mechanism of the corresponding structural, micro-structure, elemental composition and distribution, magnetic, cations exchange, and micro-magnetic behavior was profoundly revealed. Under microscopic examinations, the optimum composition at x = 0.02 with well-arranged spinel structure, dense texture with expected elemental composition, favorable soft magnetic properties and micro-magnetic behaviors is evident. Fortunately, this optimum is in coincidence with the achievable maximum magneto-mechanical coefficient, even the macroscopic electric properties with stronger magnetoelectric (ME) interactions and higher power conversion efficiency (PE) in tri-layered ME samples as expected. Experimental results show that the eventual PE reaches its maximum of 75.67 % under Ropt = 33kΩ for samples at x = 0.02, and exhibit a 2.24 times higher PE than that of sample without samarium substitution. These findings provide a holographic perspective to connect the microscopic beneficial effects of materials to bulk device that are promising for efficient power conversion solid-state electronics.

Nanoprecipitation induced giant magnetostriction: A time-resolved small-angle neutron scattering study of the vacancy-assisted kinetics

Solid-state precipitation is an effective strategy for tuning the mechanical and functional properties of advanced alloys. Structure design and modification necessitate good knowledge of the kinetic evolution of precipitates during fabrication, which is strongly correlated with defect concentration. For Fe-Ga alloys, giant magnetostriction can be induced by the precipitation of the nanoscale tetragonal L60 phase. By introducing quenched-in vacancies, we significantly enhance the magnetostriction of the aged Fe81Ga19 polycrystalline alloys to ∼305 ppm, which is close to the level of single crystals. Although vacancies were found to facilitate the generation of the L60 phase, their impact on the precipitation mechanism and kinetics has yet to be revealed. This study combined transmission electron microscopy (TEM) and time-resolved small-angle neutron scattering (SANS) to investigate the precipitation of the L60 phase during the isothermal aging at 350 and 400 °C, respectively. The evolution of L60 nanophase in morphology and number density in as-cast (AC) and liquid nitrogen quenched (LN) Fe81Ga19 alloys with aging time were quantitatively compared. Interestingly, the nucleation of the L60 phase proceeds progressively in AC while suddenly in LN specimens, indicating the homogenous to heterogeneous mechanism switching induced by concentrated vacancies. Moreover, excess vacancies can change the shape of nanoprecipitates and significantly accelerate the growth and coarsening kinetics. The magnetostrictive coefficient is optimized when the size (long-axis) of L60 precipitates lies between 100 and 110 Å with a number density between 3.2–4.3 × 10–7 Å–3. Insight from this study validates the feasibility of achieving high magnetoelastic properties through precise manipulation of the nanostructure.

Magnetic field dependent elastic moduli and internal frictions in nickel alloy revealed by a quantitative electromechanical impedance method

Accurately and quickly determining the moduli and damping properties of ferromagnetic materials with bias magnetic fields is very important for vibration control and instrument design. In this work, the magnetoelastic properties of a nickel alloy were investigated by using a quantitative electromechanical impedance (Q-EMI) method under bias magnetic fields from 0 to 1364 Oe. Measurement results demonstrate that both the Young’s modulus and shear modulus of the nickel increase steadily with the bias magnetic field, tending to saturate under high fields. The internal friction of nickel initially increases and subsequently decrease with the magnetic field, exhibiting a pronounced peak. Meanwhile, it is found that the torsional internal friction is always considerably larger than the longitudinal internal friction. The amplitude dependent internal friction (ADIF) of the nickel alloy under bias magnetic fields was further studied using a dog-bone shaped specimen and a strain-amplifier horn. Results show that the specimen under zero field shows the most significant ADIF when the strain amplitude exceeds 2 ⅹ 10−5. While under a large bias field over 1000 Oe, the ADIF cannot appear until the strain amplitude is over 1 ⅹ 10−4 strain, indicating that the ferromagnetic domains had been stabilized by the large bias field. This study demonstrates the superiority of the Q-EMI method in probing the magnetomechanical properties of ferromagnetic materials.

Structural, Opto-Electronic and Magneto-Elastic Properties of Tetra One Type Layered EuCuFS/Se Magnetic Semiconductor for Diverse Applications: A First-Principles Study

Structural, Opto-Electronic and Magneto-Elastic Properties of Tetra One Type Layered EuCuFS/Se Magnetic Semiconductor for Diverse Applications: A First-Principles Study

Optimizing magnetoelastic properties by machine learning and high-throughput micromagnetic simulation

Optimizing magnetoelastic properties by machine learning and high-throughput micromagnetic simulation

Intrinsic multiferroic semiconductors with magnetoelastic coupling: two-dimensional MoTe<i>X</i> (<i>X</i> = F, Cl, Br, I) monolayers

Two-dimensional materials with both ferromagnetism and ferroelasticity present new possibilities for developing spintronics and multifunctional devices. These materials provide a novel method for controlling the direction of the magnetization axis by switching the ferroelastic state, achieving efficient and low-power operation of magnetic devices. Such properties make them a promising candidate for the next generation of non-volatile memory, sensors, and logic devices. By performing the first-principles calculations, the ferromagnetism, ferroelasticity, and magnetoelastic coupling in MoTe<i>X</i> (<i>X</i> = F, Cl, Br, I) monolayers are systematically investigated. The results indicate that the MoTe<i>X</i> monolayers are intrinsic semiconductors holding both ferromagnetism and ferroelasticity. The pronounced in-plane magnetic anisotropy suggests that the MoTe<i>X</i> monolayers can resist thermal disturbances and maintain long-range magnetic order. The Curie temperatures of MoTe<i>X</i> monolayers are 144.75 K, 194.55 K, 111.45 K, and 92.02 K, respectively. Our calculations show that the four MoTe<i>X</i> monolayers possess two stable ferroelastic states, with their easy magnetization axes perpendicular to each other. The ferroelastic transition barriers between the two ferroelastic states of MoTeF, MoTeCl, MoTeBr, MoTeI monolayers are 0.180 eV/atom, 0.200 eV/atom, 0.209 eV/atom, and 0.226 eV/atom, respectively, with their corresponding reversible strains of 54.58%, 46.32%, 43.06%, and 38.12%. These values indicate the potential for reversible magnetic control through reversible ferroelastic transition at room temperature. Owing to their unique magnetoelastic coupling properties, MoTe<i>X</i> monolayers exhibit the ability to control reversible magnetization axis at room temperature, laying the foundation for the development of highly controllable and stable spintronic devices.

Коэффициенты электромагнитных связанностей композита "пьезоэлектрик / феррит" с учетом реальной структуры и начальных напряжений

New improved analytical solutions are obtained for tensors of effective pyro– electro–magneto–elastic properties of a piezoactive composite at initial stress-strain state (resulting from initial loading) that account for real two-point correlation functions of an irregular quasi-periodic random structure. The calculations of effective coefficients of electromagnetic and magnetoelectric coupling of the transversal isotropic unidirectional fibrous composite "PZT-4/ferrite" with an axisymmetric tensor of initial strain of the composite are presented. An increase in the absolute values of the effective coefficients is observed at negative (compressive) values of the initial strain tensor components of the composite.

Mathematical micro–macro modeling of fully coupled nonlinear magneto-elastic reinforced composites

In this paper, integral equation formulations and field-dependent micromechanical modeling of global nonlinear magneto-mechanical behavior of magneto-elastic composites under high strain and magnetic field are elaborated. The modeling is obtained based on an extension of micro–macro transition inclusion problem to nonlinear behavior using field-dependent and highly nonlinear localization tensors. A methodological procedure is elaborated based on newly introduced strain and magnetic field-dependent Green tensors, strain and magnetic field-dependent integral equations linked to tensors of Eshelby and micromechanical approaches. The field-dependent global moduli are predicted based on the Mori–Tanaka approach and self-consistent method. Iterative incremental schemes based on the Newton–Raphson and fixed-point algorithms are examined and established precise semi-analytic equations of the effective magneto-elastic properties of composites that are dependent on the magnetic-strain field for different types of inclusions. A numerical code is elaborated for numerical predictions and the obtained field-dependent effective magneto-elastic coefficients are obtained and presented for various volume fractions of inclusion, types and shapes of the reinforced nonlinear composites.

Non-stoichiometric TbFe2Mnx compounds: Magnetic anisotropy, magnetostriction and thermal expansion

In magnetostrictive RFe2 (R – rare earth) materials, magnetic properties such as magnetocrystalline anisotropy and Curie temperature can have a profound impact on the magnetostriction, often reducing its value in practically applicable magnetic field at normal conditions. Tuning the atomic structure by Mn alloying is one of the research strategies that allows to improve both elastic and magnetoelastic properties. Here we investigate novel non-stoichiometric TbFe2Mnx (0 ≤ x ≤ 0.25) compounds in which Mn partially replaces both Tb and Fe. Curie temperature and magnetic moment values decrease with manganese alloying. We interpret these effects as a consequence of lowered Fe-Fe exchange interactions which is confirmed within two-sublattice molecular field model. Magnetocrystalline anisotropy estimated by law of approach to magnetic saturation in high pulsed magnetic fields shows trend of decrease with Mn doping. Notably, this cause significant increase of linear magnetostriction (up to 25%) for TbFe2Mnx compounds at liquid nitrogen temperature. Thermal expansion declined due to growth of magnetic contribution in magnetically ordered state, which is linked to volume magnetostriction. These changes make TbFe2Mnx promising material for practical application. Thus, it was shown that manganese alloying opens new way for tuning magnetocrystalline anisotropy and magnetostriction in non-stoichiometric Laves phase compounds.

Strain-magneto-optics: Magnetoreflectivity in MnFe2O4 ferrite-spinel crystal

The single crystal of ferromagnetic magnetostrictive spinel MnFe2O4 was grown by the zone-floating method. The magnetic, magneto-elastic, optical, and magneto-optical properties of the MnFe2O4 ferrite-spinel were investigated in the infrared spectral range. A strain-magneto-optical phenomenon, which demonstrate the connection between magnetoreflection of non-polarized light and magnetostriction of MnFe2O4, was revealed. A maximum magnetoreflection of up to 1 % was observed at room temperature in a magnetic field of 2 kOe. Using the Kramers-Kronig method, the magnetorefractive effect and magnetooptical conductivity of MnFe2O4 were also calculated. The observed correlation between magnetoelastic and magneto-optical properties of MnFe2O4 was attributed to the significant contribution of linear magnetostriction to the magnetic anisotropy constant (ΔK/K1 ∼ 8 %) in the MnFe2O4 crystal. Additionally, a criterion of ΔK/K1 ∼ 1 % was proposed to evaluate the potential use of magnetostrictive materials in strain-magneto-optics.

Influence of the strain effect on magnetocrystalline anisotropy in Co2Fe0.4Mn0.6Si Heusler alloys

The perpendicular magnetocrystalline anisotropy, magnetoelastic properties as well as the Gilbert damping factor in Co2Fe0.4Mn0.6Si thin films were found to depend on a magnetic layer thickness, and they can be also tuned by the application of additional Ag buffer layer. The tetragonal distortion of a magnetic layer was found to increase with decreasing thickness, and after the application of an additional Ag buffer layer, the character of this distortion was changed from tensile to compressive in the plane of a film. A correlation between the tetragonal distortion and perpendicular magnetocrystalline anisotropy was found. However, the magnitude of the observed tetragonal distortion for most samples seems to be too small to explain alone the experimentally found large magnitude of the perpendicular magnetocrystalline anisotropy. For these samples, other mechanisms including both surface and volume effects must be taken into account.

Phase transitions and the magnetocaloric effect in (Gd,Tb)5Si2Ge2 compounds doped with Ti

We have conducted the study of structural, magnetic, magnetothermal, and magnetoelastic properties of four rare-earth compounds: Gd4.5Tb0.5Si2Ge2, Gd4TbSi2Ge2, Gd4.4Tb0.5Ti0.1Si2Ge2, and Gd3.9TbTi0.1Si2Ge2 in the vicinity of magnetically induced phase transitions. We demonstrate that the introduction of Ti into the rare-earth sublattice separates the structural and magnetic phase transitions and changes the order of magnetic phase transition from type I to II, while preserving high values of magnetocaloric effect (MCE). Additionally, incorporating a small quantity of Tb enables the creation of compounds with enhanced MCE values over a specific temperature range of 240–290 K. The observed phenomena can be attributed to the combined effects of forced magnetization and alteration of magnetic susceptibility during the structural phase transition that accompany the magnetic phase changes in these compounds.

Non-stoichiometric ErFe2Mnx compounds: Structure, magnetic, magnetoelastic and magnetothermal properties

Crystal structure, magnetostriction, magnetic and magnetothermal properties have been studied for novel non-stoichiometric ErFe2Mnx (0 ≤ x ≤ 0.6) compounds. It has been found that for х ≤ 0.4 the compounds crystallize with MgCu2-type structure. Curie temperature and magnetic moment values decrease with manganese alloying. Molecular field coefficients have been calculated within ferrimagnetic two-sublattice molecular field model. Magnetic and heat capacity measurements have been used to calculate magnetocaloric effect in a wide temperature range. It has been demonstrated that increasing the Mn content in ErFe2Mnx leads to a significant increase (up to 39 %) of anisotropic magnetostriction value at 77 K in magnetic field of 18 kOe. At the same time, the value of effective magnetocrystalline anisotropy decreases. Thus, manganese alloying opens new way for tuning magnetocrystalline anisotropy and magnetostriction in Laves phase compounds.

Magnetic and magnetoelastic properties of LiYbF4 crystal in the strong magnetic field

This work presents the results of experimental and theoretical studies of the magnetic properties of the LiYbF4 single crystal and powder samples, and magnetoelastic properties of the LiYbF4 single crystal samples, at low temperature and applied field range of 0-9 T. The magnetostriction experimental data for the single crystal of LiYbF4 is published for the first time. The magnetization and magnetostriction were calculated in the framework of the exchange-charge model taking into account dipole–dipole and electron-deformation interactions, with the calculation of the electron-deformation parameters. The theoretical analysis presents quantitative agreement in the temperature range of 2–10 K with the magnetization and magnetostriction measurements of the LiYbF4 samples.