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A moment and axial force sensor using a self-decoupled, passive and wireless method was proposed, designed, analyzed, fabricated and tested. A specially designed mechanical structure based on a joint ball bearing was proposed to realize the intrinsic self-decoupling operation. Two pieces of Metglas 2826MB magnetostrictive material were attached at predesignated positions on a mechanical structure to detect the moment and axial force separately. The magnetostrictive material enabled the passive and wireless detection based on the Villari effect. An analysis model was established to derive the relationship between the input forces and output voltages. Experiments were carried out to verify the self-decoupling performance, dynamic performance, drift performance and hysteresis performance of the sensor. We proved that the decoupling error of the sensor was less than 2.4%, the dynamic error of the sensor was less than 6.15%, and the sensor could fulfill passive and wireless detection. Compared with traditional multidimensional sensors, our sensor showed advantages of intrinsic self-decoupling, passive and wireless, and dynamic detection. These advantages enable the sensor to have potential applications in cutting tool force detection, sealed gearboxes, etc.

In this study, a simply supported functionally graded material beam with a giant magnetostrictive thin film (GMF) was selected as an energy harvester. Based on the theory of large deformation and the Villari effect of GMF, piston theory was used to simulate the dynamic equation of the whole structure under supersonic aerodynamic pressure and in a thermal environment by using Hamilton’s principle, and the energy harvesting effect of GMF was simulated by using a Runge–Kutta algorithm. Below the critical flutter velocity, the maximum voltage output and energy harvesting results were discussed as they were affected by external factors such as the geometric model of structure parameters, slenderness ratio, gradient index, number of turns of an electromagnetic coil, airflow velocity, and temperature. The electromechanical coupling coefficient $$ k_{{33}}$$ was 71%. The results show that this proposed harvester can achieve an optimal harvesting effect by adjusting the parameters appropriately, and collect energy in thermal and supersonic environments using the GMF, which provides power to sensors of the health monitoring system of the aircraft’s own structure.

The influence of temperature on the magnetization distribution of planar Co18Ni82 microparticles deposited on a lithium niobate single crystal was studied using the magnetic force microscopy and co...

Targeted magnetic flux guidance in the rotor cross section of rotational electrical machines is crucial for the machine’s efficiency. Cutouts in the electrical steel sheets are integrated in the rotor sheets for magnetic flux guidance. These cutouts create thin structures in the rotor sheets which limit the maximum achievable rotational speed under centrifugal forces and the maximum energy density of the rotating electrical machine. In this paper, embossing-induced residual stress, employing the magneto-mechanical Villari effect, is studied as an innovative and alternative flux barrier design with negligible mechanical material deterioration. The overall objective is to replace cutouts by embossings, increasing the mechanical strength of the rotor. The identification of suitable embossing geometries, distributions and methodologies for the local introduction of residual stress is a major challenge. This paper examines finely distributed pyramidal embossings and their effect on the magnetic material behavior. The study is based on simulation and measurements of specimen with a single line of twenty embossing points performed with different punch forces. The magnetic material behavior is analyzed using neutron grating interferometry and a single sheet tester. Numerical examinations using finite element analysis and microhardness measurements provide a more detailed understanding of the interaction of residual stress distribution and magnetic material properties. The results reveal that residual stress induced by embossing affects magnetic material properties. Process parameters can be applied to adjust the magnetic material deterioration and the effect of magnetic flux guidance.

The performance of a vibration power generator using a single crystal core of Fe–Ga alloy was compared with that of a generator using a Fe–Ga alloy polycrystal core with a similar Ga concentration. When the generator using the polycrystal core was forcibly vibrated by 1-G acceleration, the vibration frequency dependence of the open-circuit voltage showed a peak with a maximum value of about 0.14 V at the first resonance frequency due to the inverse magnetostrictive effect. On the other hand, the generator using a single crystal core with a direction parallel to the external stress direction exhibited a maximum value of about 0.26 V, about two-times larger than that of the device using the polycrystal core. Consequently, a vibration energy generator using a single crystal core of Fe–Ga alloy has advantages in performance over a generator using a polycrystal core.

The integration of magneto-electric and spintronic sensors to flexible electronics presents a huge potential for advancing flexible and wearable technologies. Magnetic nanowires are core components for building such devices. Therefore, realizing flexible magnetic nanowires with engineered magneto-elastic properties is key to flexible spintronic circuits, as well as creating unique pathways to explore complex flexible spintronic, magnonic, and magneto-plasmonic devices. Here, we demonstrate highly resilient flexible ferromagnetic nanowires on transparent flexible substrates for the first time. Through extensive magneto-optical Kerr experiments, exploring the Villari effect, we reveal an ultralow magnetostrictive constant in nanowires, a two-order reduced value compared to bulk values. In addition, the flexible magnetic nanowires exhibit remarkable resilience sustaining bending radii ∼5 mm, high endurance, and enhanced elastic limit compared to thin films of similar thickness and composition. The observed performance is corroborated by our micro-magnetic simulations and can be attributed to the reduced size and strong nanostructure-interfacial effects. Such stable magnetic nanowires with ultralow magnetostriction open up new opportunities for stable surface mountable and wearable spintronic sensors, advanced nanospintronic circuits, and for exploring novel strain-induced quantum effects in hybrid devices.

Deformation-induced martensitic transformation (DIMT) has been investigated for many years mainly under monotonic loading conditions. However, the evolution of the DIMT under non-monotonic loading conditions has rarely been studied. The present work experimentally explored the development of DIMT under tension-compression as well as torsion cyclic loading conditions and showed fluctuating behavior within loading cycles in austenitic stainless steels measured by Feritscope, which was not observed under monotonic loadings. The present study showed that the fluctuation of the martensite measurement was related to the dual-phase features and could be explained by the Villari effect in the martensite phase. The martensite contents are assumed to increase monotonically with the effective plastic strain and are distributed along with principal stresses. A unified kinetics model for DIMT was proposed for both monotonic and cyclic loading conditions and verified experimentally. The anisotropic development of DIMT can be described by the model in combining with cyclic plasticity.

This paper presents the study results on the fabrication of a structural integrity assessment apparatus by determining stress concentration zones in pressure pipeline and equipment. The apparatus uses a triaxial magnetic field sensor to measure magnetic field components in three axes Ox, Oy, and Oz, in the working range of the magnetic field from -300 µT to 300 µT. The investigation of the selfmagnetic leakage field by this apparatus in the API 5L steel specimens under tensile stress shows a high variation of the magnetic field at a steel elongation lower than 1 mm (corresponding to the elastic deformation state of the material). In the case of an artificial defect, the apparatus can detect a change in the magnetic field caused by stress concentration.

The changes in the domain structure of CoNi microparticles under action of mechanical stresses have been studied. With this purpose, an array of identical planar square CoNi particles has been formed on the surface of a polished glass substrate. An elastic bending of the substrate has been used to induce mechanical stresses in the particles. It is shown, using magnetic-force microscopy, that the magnetic structure of the particles can be changed from the multidomain to quasi-homogeneous magnetization using mechanical stresses.

In the article, it was experimentally determined that compressive mechanical stress affects the parameters of the temperature dependence of the initial permeability. LiTiZn ferrite ceramics were sintered at 1010 °C for 2 h in air. The experimental curves were mathematically processed using the phenomenological expression to describe the initial magnetic permeability according to the Smith-Wijn model. It is shown that the change in the shape of the experimental curves correlates with the calculated data of the increase in the demagnetizing factor with an increase in mechanical stress. It is hypothesized that the change in the shape of the temperature curves is due to the magnetoelastic effect and the temperature dependence of the magnetostriction constant. Also, it was found that mechanical stress does not affect the X-ray microstructural parameters, including the true physical broadening of the reflexes. At the same time, the growth of mechanical stress to the maximum possible level for such type of ferrite ceramics leads to an increase in the coercive force by 10%. The character of the impact of mechanical stress on the shape of the temperature dependence curve of the initial permeability differs from the effect of non-magnetic Al2O3 additives. Thus the character of the change in the shape of the temperature dependence curve of the initial permeability allows monitoring nonmagnetic phases or mechanical stress in a LiTiZn ferrite ceramics production.

A self-powered magnetostrictive sensor (SMS) for long-term earthquake monitoring is proposed in this article. A piece of magnetostrictive material was bonded on the upside surface of a stainless steel plate to form the proposed sensor. A force was applied on the free end of the sensor to mimic an earthquake vibration. The applied stress led to a varied permeability of the magnetostrictive material according to the Villari effect. Then, the varied permeability produced a varied magnetic field. The varied magnetic field was captured by a coil to generate electric power for an earthquake alarm. A theoretical analysis was investigated in this article. After the fabrication of a sensor prototype, the vibration characteristics and voltage output ability were measured. The maximum vibration amplitude and maximum output trust voltage were tested to be 25 mm and 0.38 V (peak to peak) under an applied force of 2 N. The proposed SMS exhibits merits of simple structure, small size, easy fabrication, and long-term working ability.

A laboratory setup is considered intended for special physics workshops and demonstration experiments of a lecture course in general physics as well for a study of elastic waves and magnetoelastic phenomena in ferromagnets in a standing wave field excited in a piezoceramic resonator. The acoustic signal and the magnetoelastic response are recorded simultaneously with a dual channel oscilloscope. The ferromagnet is magnetized using Helmholtz coils. The position of the nodes and antinodes in the standing wave of the electromagnetic signal along the length of the rod was determined with a scanning coil, and the wavelength, sound velocity, and elastic modulus were calculated from these data. The properties of standing waves a ferrite and a steel rod as well as on electrical steel tape 50 μm thick glued to a glass rod have been investigated.

The magnetoelectric properties of exchange-coupled Ni/CoFeB-based composite multiferroic microstructures are investigated. The strength and sign of the magnetoelastic effect are found to be strongly correlated with the ratio between the thicknesses of two magnetostrictive materials. In cases where the thickness ratio deviates significantly from one, the magnetoelastic behavior of the multiferroic microstructures is dominated by the thicker layer, which contributes more strongly to the observed magnetoelastic effect. More symmetric structures with a thickness ratio equal to one show an emergent interfacial behavior which cannot be accounted for simply by summing up the magnetoelastic effects occurring in the two constituent layers. This aspect is clearly visible in the case of ultrathin bilayers, where the exchange coupling drastically affects the magnetic behavior of the Ni layer, making the Ni/CoFeB bilayer a promising next-generation synthetic magnetic system entirely. This study demonstrates the richness and high tunability of composite multiferroic systems based on coupled magnetic bilayers compared to their single magnetic layer counterparts. Furthermore, because of the compatibility of CoFeB with present magnetic tunnel junction-based spintronic technologies, the reported findings are expected to be of great interest for the development of ultralow-power magnetoelectric memory devices.

A magnetostrictive tactile sensing unit and the integrated sensor array have been developed, based on the sensing process of human skin and the inverse magnetostrictive effect. The working mechanism of the magnetostrictive tactile sensing unit has theoretically been studied by using electromagnetism theory and cantilever beam theory, and the relationship between the applied force and output voltage has been determined. The measurement of sensing performance about the static and dynamic force has been carried out, and it is found that the sensitivity of a sensing unit is 127 mV/N, resolution is 0.07 N, and response time is 24 ms. The sensing unit possesses a high reliability with the test of 5 000 cycles. The optimum distance between adjacent sensing units of the sensor array is determined by COMSOL multiphysics software when the sensing unit is integrated into a sensor array. By integrating four magnetostrictive tactile sensing units into a 2 $\times 2$ sensor array, it could monitor and map the force distribution applied on the manipulator in the grip. The tactile sensor array shows great potential within the application of intelligent manipulator.

Self-decoupled and passive characteristics are crucial requirements for a multi-dimensional sensor. A T-type self-decoupled and passive dynamic tension and torque sensor was proposed, analyzed, and fabricated. The sensor mainly consisted of a T-type torque deforming block, a force deforming ring, and a torque shaft. The T-type torque deforming block withstood the torque individually; the force deforming ring bore the tension force separately; and the decoupling of the tension force and torque was realized by the torque shaft. After that, the tension force and torque were measured, respectively. The decoupling operation was fully completed by mechanical structure. Two pieces of magnetostrictive material were pasted on the T-type torque deforming block and force deforming ring as the sensing units. The passive feature was fulfilled by the magnetostrictive material via the Villari effect. Finite Element Method (FEM) analysis was carried out to verify the decoupling principle. The sensor was fabricated, and then the experiments were conducted. The results showed that the sensor had a good decoupling ability. The sensor could work dynamically with a voltage deviation less than 0.5 mV. The force and torque ranges of the sensor were 1000 N and 6.5 $\text{N}\cdot \text{m}$ respectively. The sensor could also work effectively in a passive state. Furthermore, the sensor displayed the advantages of being wireless, the ability to work dynamically and in a liquid environment. Thus, this sensor could be mounted on a cutting tool of a machine center to detect the compound force on the cutting tool.

Magnetoelastic effect characterizes the change of materials’ magnetic properties under mechanical deformation, which is conventionally observed in some rigid metals or metal alloys. Here we show magnetoelastic effect can also exist in 1D soft fibers with stronger magnetomechanical coupling than that in traditional rigid counterparts. This effect is explained by a wavy chain model based on the magnetic dipole-dipole interaction and demagnetizing factor. To facilitate practical applications, we further invented a textile magnetoelastic generator (MEG), weaving the 1D soft fibers with conductive yarns to couple the observed magnetoelastic effect with magnetic induction, which paves a new way for biomechanical-to-electrical energy conversion with short-circuit current density of 0.63 mA cm−2, internal impedance of 180 Ω, and intrinsic waterproofness. Textile MEG was demonstrated to convert the arterial pulse into electrical signals with a low detection limit of 0.05 kPa, even with heavy perspiration or in underwater situations without encapsulations., The authors invented a textile magnetoelastic generator, weaving 1D soft fibers with conductive yarns to couple the observed magnetoelastic effect with magnetic induction, which paves a new way for biomechanical-to-electrical energy conversion.

A new type of sensor unit is designed, based on the simulation of hair structure and the magnetic sensitive material Galfenol filament, which was integrated into an array. The output characteristic model of the sensor unit is established according to inverse magnetostrictive effect, linear piezomagnetic equation, and material mechanics. The experimental results show that the output voltage of the sensor unit varies linearly under the action of 0–2.4 N. The sensor array has a good stability and response speed. According to the characteristic of tire pattern, a tire pattern sample is selected to measure. A test system is built for data acquisition and storage, and the output characteristics of the sensor array are tested. The integrated sensor array can well identify the pattern characteristics of the selected tire sample, and the maximum absolute error is 0.7 mm.

${\mathrm{Ca}}_{3}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ is a correlated and spin-orbit coupled system with an extraordinary anisotropy. It is both interesting and unique largely because this material exhibits conflicting phenomena that are often utterly inconsistent with traditional precedents, particularly, the quantum oscillations in the nonmetallic state and colossal magnetoresistivity achieved by avoiding a fully spin-polarized state. This work focuses on the relationship between the lattice and transport properties along each crystalline axis and reveals that application of magnetic field, $H$, along different crystalline axes readily $\mathit{stretches}$ or $\mathit{shrinks}$ the lattice in a uniaxial manner, resulting in distinct electronic states. Furthermore, application of modest pressure drastically amplifies the $\mathit{anisotropic}$ magnetoelastic effect, leading to either an occurrence of a robust metallic state at $H||\mathrm{hard}$ axis or a reentrance of the nonmetallic state at $H||\mathrm{easy}$ axis. ${\mathrm{Ca}}_{3}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ presents a rare lattice-dependent magnetotransport mechanism, in which the extraordinary lattice flexibility enables an exquisite control of the electronic state via magnetically stretching or shrinking the crystalline axes, and the spin polarization plays an unconventional role unfavorable for maximizing conductivity. At the heart of the intriguing physics is the anisotropic magnetostriction that leads to exotic states.

The severe acute respiratory syndrome coronavirus (SARS-CoV-2) has spread rapidly around the world. In order to prevent the spread of infection, city blockades and immigration restrictions have been introduced in each country, but these measures have a severe serious impact on the economy. This paper examines the possibility of both harvesting vibration energy and detecting mass by using a magnetostrictive alloy. Few efforts have been made to develop new magnetostrictive biosensor materials. Therefore, we propose magnetostrictive Fe-Co/Ni clad steel vibration energy harvesters with mass detection, and we numerically and experimentally discuss the effect of the proof mass weight on the frequency shift and output voltage induced by bending vibration. The results reveal that the frequency and output voltage decrease significantly as the mass increases, indicating that the energy harvesting device is capable of mass detection. In the future, device miniaturization and the possibility of virus detection will be considered.

Magnetostrictive materials are useful for actuators, sensors. In this work, a Hall sensor is integrated in a magnetostrictive micromechanics. Deformation of the magnetostrictive material induces the change of magnetization, which is detected by the Hall sensor. In order to demonstrate this concept, a FeGa-Si biomaterial cantilever with a Si Hall sensor is microfabricated. FeGa thin film is deposited by a novel electroplating method. The Hall sensor signal can be obtained when the cantilever is vibrated at its resonant frequency. This Hall sensing element integration is effective way for the detection of strain and vibration of micromechanics.

A torque measurement method that combines the inverse magnetostrictive effect with twist angle measurement has been proposed in this paper. A Kalman filter and complementary filter are applied to significantly reduce the noises and errors in the proposed method. This new measurement block can detect the applied torque with an error of less than 1%. The proposed measurement method can be used in static and dynamic conditions.

The effect of deformations on magnetic nanoparticles of elliptic, square, and triangular shapes is simulated. The distribution of the magnetization of such particles is studied as functions of their shapes and applied deformations. A deformation is shown to possibly lead to the formation of new metastable states and also a change in the type of the ground state of a particle. The deformation substantially changes the distribution of the particle magnetization, which can be detected by their MFM contrast.

The inverse magnetostrictive response (i.e. a change in magnetization due to an applied stress) of magnetostrictive materials, the Villari effect is widely applied for sensor applications. Mechanical properties are an important factor when applied for vibration energy and sensor applications. Surface-treatment methods are widely used for enhanced performance and serviceability of engineering components, and nitriding is one of the most versatile surface engineering method nowadays. These methods allow the fine tuning of surface quality-dependent properties such as the resistance to fatigue, wear, and corrosion. In this study, the change of inverse magnetostrictive characteristics of Co-rich Fe-Co bimetals by the nitriding treatment, for 30 min at 580 °C, was evaluated. The effect of the nitriding treatment on the inverse magnetostrictive characteristics, magnetostrictive susceptibility and magnetic hysteresis loop of Fe-Co bimetals, by an applied load, were evaluated by three-point bending tests under a magnetic field. Furthermore, the output voltage of the as-rolled Fe-Co/Ni bimetal and the nitrided Fe-Co/Ni bimetal cantilevers, under bending vibration, were compared. The nitride Fe-Co/Ni bimetal construct exhibited a high output voltage compared to the as-rolled Fe/Ni bimetal.

Tactile sensing is used to explore and manipulate objects, which is essential for the interaction with the environment. A novel magnetostrictive tactile sensor array for use in robotic fingers based on smart material, Fe83Ga17 alloy (Galfenol), was proposed. According to the electromagnetism theory, cantilever beam theory, and inverse magnetostrictive effect, the force measurement model of the sensor has been established. The theoretical analysis and experimental verification for the sensor have been carried out. The sensor is sensitive to the force 0–2 N, the maximum value of output voltage is 96.13 mV. We implement the feature extraction and the tactile object recognition on data acquired during an underactuated manipulator equipped with the magnetostrictive tactile sensor array. The actuator positions and tactile sensor values were considered to be available feature data. The proposed approach does not require force modulation and is suitable for gripping arbitrary initial position and orientation of object, so the tactile sensing system can be integrated into the actual robotic gripping and recognizing scenes.

Purpose The purpose of this study is to develop an output model to extract surface microstructure characteristics of different objects, so as to predict the response of the output voltage obtained from tactile texture sensor. Design/methodology/approach The model is based on the consideration of the inverse-magnetostrictive effect, the flexure mode, the linear constitutive equations and the strain principle. Findings This research predicts and investigates the effect of the texture properties on the tactile texture sensor output characteristics. Originality/value The surface texture characteristic is regarded to be important information to evaluate and recognize the object.

A novel magnetoelastic-based sensor (MBS) is proposed in this paper to monitor the force of artificial bone (AB) using magnetoelastic material as the sensing element based on the inverse magnetoelastic effect. The MBS is embedded inside the AB using novel 3-D printing technology (N3DPT). Seven ABs are fabricated by N3DPT and tested by self-developed experimental devices to select the optimum output position of MBS and explore the relationship between the external force working on the AB and the varying value of output power (VOP) caused by the MBS. The applied force of the AB covered by biological tissue is also further monitored using MBS. Results indicate that the middle position ( $h=0$ ) of the AB can fully express the performance of MBS and clearly reflect and monitor the applied force of the AB using a wireless and passive method. An increase of external force working on the AB can cause a rise in output power of the sensing coil which is 0.5 dbm of the VOP under 100 N external force. This further demonstrates that the MBS can efficiently monitor the force of AB and prosthesis in vitro and in vivo .

Alternating Current Potential Drop (ACPD) measurements are routinely used for monitoring crack length in laboratory based fatigue tests, and so measurements will be taken on components which are exposed to cyclic dynamic stresses. It has been empirically observed that cyclic stresses cause a strong increase (above 10% is shown in this paper) in measured resistance that is both AC inspection frequency and loading frequency dependent. The excess resistance will result in erroneous measurements; this paper investigates the cause and provides recommendations to limit the influence. Applied stresses influence ACPD measurements through the magnetoelastic effect; elastic strain induces magnetization in ferromagnetic materials, which in turn influences the magnetic permeability and therefore skin depth. Further, it has recently been realised that cyclic magnetization results in a frequency dependent concentration of the magnetic flux at the surface of the component, and consequently a non-uniform spatial distribution of magnetic permeability. In this study it is found that the interaction between the non-uniform spatial distribution of both the current density and magnetic permeability results in significant non-linear modulation of the measurement signal. A combination of finite element simulations and experimental results are used to explore this phenomenon.

A novel magnetostrictive tactile sensor has been designed, based on the inverse magnetostrictive effect and bionics, which can be used to test the gripping force of a manipulator and to detect the stiffness of the manipulated objects. Based on the electromagnetics theory, the inverse magnetostrictive effect, and the Hooke's law, the force measurement model and the stiffness detection model have been established. A magnetostrictive tactile sensor is designed to measure the applied force from 0 to 5 N with a sensitivity of 114 mV/N. The stiffness classification of the manipulated objects has been tested with four different types of sample materials. The results indicate that the output voltage and slope can be applied as a criteria for classifying the stiffness of the manipulated objects. The magnetostrictive tactile sensor has a simple structure with a rapid response and can realize the precise perception of the manipulated objects.

An artificial bone that can harvest energy from human motion was proposed, designed, analyzed, fabricated, and tested. The proposed artificial bone was fabricated by a 3D printer. A piece of magnetostrictive material was embedded in the middle of the artificial bone as the energy harvesting component. When the artificial bone was compressed, the magnetostrictive material was also stressed, which caused a variation in the permeability, according to the Villari effect. The varied permeability led to a varied spatial magnetic field. The varied spatial magnetic field was acquired by a collecting coil, and was transmitted and stored as a kind of energy from the human motion. A theoretical analysis of the artificial bone was conducted to find factors that influence energy harvesting performance. Experimental tests of harvesting energy from the proposed artificial bone were carried out. The voltage output and its varying tendency in the artificial bone agreed with the theoretical analysis. The artificial bone prototype achieved a trust maximum voltage of 206 mV (peak-to-peak) and a trust maximum power of 0.1 mW.

High-sensitivity strain and vibration sensors were fabricated based on the inverse magnetostriction effect (Villari effect) of amorphous FeSiB films. To control the anisotropy of FeSiB, we used the residual stress of the laminated structure after annealing, which depends on the mechanical properties of the substrate, a nonmagnetic molybdenum film, and the FeSiB film. The anisotropy of the rectangular FeSiB film was induced in the width axis for a cover glass substrate and in the longitudinal direction for a Si wafer substrate. The sensors detect strain and vibration based on the impedance change associated with a high-frequency permeability change in the FeSiB film. A gauge factor of 19 900 was obtained for the sensor element on the Si wafer. When an edge load of 2 g was attached to the free edge of a cantilever structure for the sensor element on the cover glass substrate, weak vibrations with an acceleration of 0.1 m/s 2 in a frequency range of 10-100 Hz could be detected.

Tuning the magnetic properties of materials is a demand of several technologies; however, our microscopic understanding of the process that drives the enhancement of those properties is still unsatisfactory. In this work, we combined experimental and theoretical techniques to investigate the handling of magnetic properties of FeCo thin films via the thickness-tuning of a gold film used as an underlayer. We grow the samples by the deposition of polycrystalline FeCo thin films on the Au underlayer at room temperature by a magnetron sputtering technique, demonstrating that the lattice parameter of the sub-20 nm thickness gold underlayer is dependent on its thickness, inducing a stress up to 3% in sub-5 nm FeCo thin films deposited over it. Thus, elastic-driven variations for the in-plane magnetic anisotropy energy, Ku, up to 110% are found from our experiments. Our experimental findings are in excellent agreement with ab initio quantum chemistry calculations based on density functional theory, which helps to build up an atomistic understanding of the effects that take place in the tuning of the magnetic properties addressed in this work. The handling mechanism reported here should be applied to other magnetic films deposited on different metallic underlayers, opening possibilities for large-scale fabrication of magnetic components to be used in future devices.

The saturation value of the magnetostriction curve in the [100] direction of a Fe-Ga alloy single crystal was decreased from 226 to 55 ppm by applying the tensile strain of 533 ppm to the measured direction. By magnetic domain observation using a magneto-optic Kerr effect microscope, a complex structure composed of various magnetic domains was observed under zero applied strain. On the other hand, a stripe structure composed of magnetic domains with the magnetization direction in two kinds of magnetic easy directions parallel to the tensile direction, which were separated by straight 180° domain walls, was observed under the tensile strain of 533 ppm. The characteristic magnetic domain structure due to the tensile strain was successfully observed as a cause of the significant decrease of the saturation value of the magnetostriction curve.

The paper presents new and original results of investigation on magnetoelastic effect in Ni-Zn ferrite formed into ring core and subjected to the axial stress up to 20 MPa. The core was magnetized with relatively low magnetizing field, corresponding to the so-called Rayleigh region. The obtained results indicate, that there is a significant correlation between applied stress and magnetic properties of the material and the Ni-Zn ferrite can be utilized in development of magnetoelastic sensor of force and stress.

The article presents the stress impedance investigation of CoFeNiMoBSi alloy in variation of the applied magnetic field. In order to carry out the study, a specialized stand was developed that allows for loading the sample with stresses and simultaneous action of the DC (direct current) magnetizing field. The tests were carried out for as-cast and Joule annealed samples. The significant influence of the magnetizing field acting on the sample on the stress-impedance results was demonstrated and the dependence of the maximum impedance change in the stress-impedance effect was determined, depending on the field acting. The obtained results are important due to the potential use of the stress-impedance effect for the construction of stress sensors.

Modern production equipment is based on the results of quality control as well as process parameters. The magnetic anisotropy of materials is closely connected to internal mechanical stress by the Villari effect, and also to hardening effects due to plastic deformations, and could therefore provide an interesting basis for process control. Nevertheless, the analysis of anisotropic properties is extremely sensitive to sensor and workpiece misalignments, such as tilting. In this work, a novel eddy current sensor system is introduced, performing a non-contact measurement of the magnetic anisotropy of a workpiece and realizing a separation and correction of tilting effects. The measurement principle is demonstrated with the example of two samples with different magnetic anisotropy values induced by cold forming. Both samples are analyzed under different tilt angles between the sensor axis and the surface of the workpiece. In this work, digital signal processing is demonstrated on the acquired raw data in order to differentiate the effects of tilt and of anisotropy, with the use of preliminary results as an example of two prepared samples.