Large Barkhausen Effect Research Articles

A Review of the Self-Powered Wiegand Sensor and Its Applications

Self-powered magnetic sensors are fundamental for the development of Industry 4.0, the Internet of things (IoT), wireless sensor networks, unmanned vehicles, smart cities, and sustainability. This review aimed to elucidate the working principles, materials, manufacture, output properties, and perspectives of Wiegand sensors. A Wiegand sensor is composed of a magnetic sensing wire, which is called a Wiegand wire, and a pick-up coil for the output of an electrical signal and energy. The Wiegand sensor requires an external magnetic field of about 70 Gauss to induce Wiegand wire flux changes, which, in turn, generate an output pulse in the pick-up coil. Output energy of more than 3000 nJ per single pulse (open circuit) can be harvested. The output pulse is derived from the large Barkhausen effect. Therefore, the behavior of the sensor output is independent of the triggering and sensing frequencies. The objective of this review article was to comprehensively highlight research endeavors devoted to Wiegand sensors. Furthermore, application scenarios of current research results are highlighted to find potential gaps in the literature and future contributions. Perspectives and research opportunities of Wiegand sensors are proposed.

Advances of amorphous wire magnetics over 27 years

AbstractAn overview of advances of the amorphous wire magnetics over the past 27 years with discoveries of extremely sensitive magnetic effects such as the large Barkhausen effect, the Matteucci effect and the magnetoimpedance effect and their successive applications to security sensor tags, pen‐inputting computer tablets and electronic compasses for mobile phones in commercial productions is presented. An important new topic of biocell magnetic field sensing in vitro and human physiological magnetic field sensing in vivo using a 10 pT amorphous wire magnetoimpedance sensor is also shown that would be improved using thinner glass‐covered amorphous wires. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Magneto impedance of electroplated NiFeMo/Cu microwires for magnetic sensors

The field and frequency dependences of the magnetic permeability in soft magnetic electroplated FeNiMo/Cu microwires were studied by means of their magneto impedance response. We analysed the influence of electroplating parameters such as current density, electrolyte composition and the presence of a magnetic field. It was found that the introduction of Mo as a third non-magnetic component causes large changes in the film permeability, which are associated with compositional and morphological effects. The electrodeposition under an external magnetic field induces a unidirectional anisotropy with the appearance of a large Barkhausen effect.

Distribution of the internal stresses in DC Joule-heated Fe77.5B15Si7.5 conventional amorphous microwires

The magnetic properties of conventional amorphous microwires are determined by the radial, azimuthal and axial internal stresses induced both during the preparation process and during suitable thermal treatments. We propose a theoretical model in order to determine the total internal stresses induced during the ‘complete’ dc Joule-heating thermal treatment (heating–crystallization–cooling). We have started from the internal stresses values obtained in the preparation process and we have found that: (i) maximal values of the axial, azimuthal and radial stresses obtained after the thermal treatment are larger than the corresponding values obtained in the preparation process, the differences being of about 350 MPa, 150 MPa and 200 MPa, respectively; (ii) the dimensions of the cylindrical inner core increase significantly (with ∼15.2%); this fact involves the appearance of a large Barkhausen effect in low axially applied magnetic fields; and (iii) the reduced remanence increases from 0.46 to 0.70.

Internal stress distribution in DC joule-heated amorphous glass-covered microwires

As known, the magnetic properties of AGCMs are determined by the radial, azimuthal andaxial internal stresses induced during both the preparation process and the suitablethermal treatments of these microwires. In this paper we have proposed a theoretical modelin order to determine the total internal stresses induced during the dc joule-heatingthermal treatment (heating–crystallization–cooling). In this view (i) we have started fromthe internal stress values obtained in the preparation process, (ii) we have considered thesupplementary axial tensile stresses due to the mechanical drawing of the microwire duringthe preparation process and (iii) we have taken into account the difference between thethermal expansion coefficients of metal and glass. We have found that (i) the maximumvalue of the axial stresses obtained after the thermal treatment is bigger thanthat obtained in the preparation process, the difference being about 450 MPa, (ii)the maximum values for the azimuthal and radial stresses decrease by and MPa respectively, (iii) the dimensions of the cylindrical inner core increase significantly(by ), which involves an increase of the degree of magnetic order in the AGCMs andconsequently leads to the appearance of a large Barkhausen effect (LBE) in low axiallyapplied magnetic fields and (iv) the reduced remanence increases from 0.90 to 0.95.

Sensors development using its unusual properties of Fe/Co-based amorphous soft magnetic wire

In this paper, the unusual properties of amorphous soft magnetic wire with Fe-based or Co-based in compositions have been discussed: giant magnetoimpedance effect (GMI), giant stress-induced impedance effect, large Barkhausen effect, magnetostriction effect. Sensor operating principles and applications exploiting these unusual properties have also been discussed: magnetic field sensors, position sensors, biosensors, non-destructive testing sensors, stress sensors etc.

High-frequency behavior of amorphous microwires and its applications

A magnetic microwire is a continuous filament of total diameter less than 100 μm consisting of an inner metallic magnetic nuclei covered by a glassy outer shell, usually obtained by Taylor's technique, with interesting magnetic properties connected with its high axial magnetic anisotropy. Magnetic sensors based on microwires used, as operating principle, the strong connection between the composition and the uniaxial anisotropy through a magnetostriction constant such as the large Barkhausen effect, Mateucci effect and giant magneto-impedance effect. The study of the microwave properties is also very promising technologically. In the microwave region (approaching GHz range), the ferromagnetic resonance (FMR) occurs and it is connected with the spin precession of the magnetisation vector due to the effect of the high-frequency electromagnetic field applied such that the magnetic component is perpendicular to the magnetisation vector. The natural ferromagnetic resonance (NFMR) has been also observed. The frequency depends upon the value of magnetic anisotropy and it is characterised by the single well-distinguished line in the 2–10 GHz range. Tags detector based on the microwires FMR and a new kind of electromagnetic radiation absorbers based on the microwires NFMR have been developed.

Po-topic IV-14: Imaging & localizing device using the barkhausen effect

We have been investigating the use of amorphous magnetic materials as locator tags for medical applications. Heinrich Barkhausen discovered in 1919 that a slow, smooth increase of magnetic field applied to a piece of ferromagnetic material, such as iron, causes the material to become magnetized not continuously, but in small steps. A large Barkhausen effect (large step change) was observed in 1931 because of domain reversal at a rapid velocity along the wire. In the late 1980s, an even larger Barkhausen effect was produced in amorphous wires giving rise to an even sharper magnetic pulse because of domain or flux reversal in the core of the wire. In an AC magnetic field, the reversal of the domains emits large, sharp magnetic pulses of the opposite sign. We are taking advantage of this pulsed response to tag and image the location and orientation of implanted devices. Several factors affect the feasibility of imaging and reconstruction of embedded tags. These include the strength of the detected signals; the ability to reconstruct locations and orientations of the tags; and signal sensitivity to tissue composition, inhomogeneities, and the presence of neighboring metals. We have obtained voltage signals from wires of several diameters with an iron-core pickup coil along a distance from the center of a wire with the coil as a function of angle for a 60–80 Hz driving field. At a distance of about 8 cm., we have obtained a strong signal of typically 2V (depending on length), more than 50 times the background noise (about 20 mV). At 30 cm separation, we detected a signal of 0.5 V, 25:1 above background noise. When the wire direction is mis-oriented relative to the driving AC magnetic field, the amplitude and phase of the resultant output signal changes. This is because only the portion of the magnetic field that is parallel to the wire axis contributes to the Barkhausen effect for that wire. By using multiple positions of the coil, we have been able to determine the changes of these two parameters for a more accurate localization. We have also determined that intervening tissues have little effect on the signals, as was expected theoretically. Our preliminary results indicate that in vivo 3D reconstruction is feasible.

大バルクハウゼン効果を用いた薄膜磁気センサの作製

We fabricated a new magnetic thin film sensor using a large Barkhausen effect. The sensor consists of a Ni-Fe thin film stripe, 0.7 mm by 4.6 mm, on a glass substrate and an aluminum thin film search coil of 400 turns on the other side of the substrate. The Ni-Fe thin film is a bi-layer composed of a soft magnetic layer and a semi-hard magnetic layer. The aluminum thin film search coil size is 6 mm by 10 mm; the line width and space are 5 μm. As a result, the sensor generated an induced pulse of about 1.4 mV by the large Barkhausen jump under asymmetrical ac magnetic fields in the frequency range from 1 to 100 Hz.

The analysis of large Barkhausen effect in the FeSiB amorphous wire

Amorphous FeSiB wires with positive magnetostriction are very perspective soft magnetic materials for many applications, e.g. torque, field or current sensors, pulse generators and highly sensitive magnetometers. The appearance of the Large Barkhausen Effect (LBE) during slow magnetization of FeSiB wires is described by means of the core-shell model assuming a residual radial tensile stresses in the as-cast state. In this work, the LBE during magnetization reversal of Fe77.5Si7.5B15 amorphous wire in the as-cast state was analysed. We have studied the kinetics of the reverse domain in the core region of the wire by means of Sixtus-Tonks method of two small pick-up coils placed in an asymmetric way with respect to the ends of the wire. We estimated the velocity of the reverse domain wall and the core region volume of the wire. It was found that the residual radial tensile stress distribution of the shell region strongly influences the magnetization reversal in the FeSiB wire.

Linear variable differential transformer sensor using Fe-rich amorphous wires as an active core

Results concerning linear variable differential transformer (LVDT) displacement measurements using Fe77.5Si7.5B15 amorphous wires as movable core are presented. Taking advantage of the large Barkhausen (LBE) effect in amorphous wire, a small exciting field and a small number of windings in the secondary coils are necessary to get an large output signal of the LVDT. The thermal noise of the output becomes low, due to the small number of coil turns, increasing thus the sensitivity of the LVDT. The results obtained show a linear dependence of the LVDT response on the displacement of the moving core for displacements up to about 14 mm, with accuracy of 1 μm.

Spinning phenomena, structure and magnetic properties of Fe–6.5 mass% Si alloy fiber produced by the in-rotating-liquid-spinning process

Almost zero magnetostrictive Fe–6.5 mass% Si alloy fibers of less than about 90 μm diameter, and showing a large Barkhausen effect, were obtained by using a laboratory scale, in-rotating-liquid-spinning process (INROLISP). The spinning conditions, jet stability, morphology of dendritic growth and magnetic properties are discussed for fibers of about 70 μm diameter with regard to manufacturing. For spinning speeds of less than about 10 m/s, the jet bounced on the surface of the rotating liquid, such as water, water with chemicals lowering the surface tension, and some oils. For speeds >10 m/s, the jet subsequently penetrated under the liquid surface after an interval of around 100 ms from the start of ejection. The centrifugal force effect was considerable in this setup. When the jet bounced, in some part of the fiber structure primary dendrite arms growing uniformly along the fiber direction were observed. In another part, however, the direction of the primary arm changed gradually far from the fiber axis and a secondary arm became the primary arm without observing a clear grain boundary. It is conceivable that the curvature of the bouncing jet at the ejection point obstructs the primary arms from growing in a straight line. When the jet penetrated, a “bamboo structure” was observed in the fiber. The penetrating jet formed a cavity of coolant downstream from the jet. This indicates that the penetrating jet firstly goes through an area of non-contact with the coolant on the cavity side while making contact with the coolant on the opposite side. Therefore, primary arms tend to grow from the contact to the cavity sides. Using the zone-annealing process, it was difficult to make a fairly long single crystal from any fiber. In order to control the continuous growth of primary arms along the fiber direction, it is suggested that a process able to cool the jet uniformly around its circumference is required so that the primary arms can grow in a straight direction. The necessary conditions to produce a fiber having a large Barkhausen effect are a nearly unidimensional shape and a [100] crystal direction of the alpha-phase parallel to the long axis. Furthermore, to obtain an ideal rectangular hysteresis loop, the requirements of a round shape in the cross section, no residual stress and no precipitation are suggested.

Production process of grain orientation-controlled Fe–6.5 mass% Si alloy fiber using spinning in gas atmosphere followed by winding in rotating liquid

A new process where a melt jet is quenched in gas followed by winding in a rotating liquid, which is a modified process of the in-rotating-water-spinning Process (INROLISP), has been developed in order to make continuous Fe–6.5 mass% Si alloy fiber with primary dendrite arms parallel to the fiber axis, having nearly zero magnetostriction. The molten alloy is ejected from a nozzle through a He gas zone located just under the nozzle, followed by an O 2 gas zone. He gas protects the orifice from plugging with metal oxides. The oxygen in the next zone forms a metal oxide sheath on the jet surface to restrain the jet from breaking up. The straight jet covered with oxide film continuously solidified and caused recalescence. After the recalescence the fiber was wound in a rotating liquid. Without the oxidization zone, such as only He or only NH 3 vapor, the jet was more rapidly cooled but became fractured. In case of CO 2 in the oxidization zone, the jet became fractured and led to short fibers. The capillary breakup length of a jet ( L BU ) can be calculated by L BU = K · V ·( ρ · d 3 / γ ) 1/2 , where V is mean velocity of a jet, ρ the density of the molten alloy, d the diameter of nozzle, and γ the surface tension of the molten alloy. In this work, the coefficient K was estimated as 10–20 from the experimental results for the He zone length and the velocity of the jet. The spinning gap between the nozzle exit and the rotating liquid surface was set 0.2–1.0 m which is longer than the length between the nozzle exit and the start of recalescence. Fibers about less than 100 μm in diameter, longer than 10 m in length, having a large Barkhausen effect were obtained.

Generation of large Barkhausen jump in bilayered thin film

A pulse voltage of half-amplitude width of approximately 20 /spl mu/s was induced in a detecting coil wound around a wire by large Barkhausen effect, when torsional stress and AC external magnetic field were applied to Fe-Co-V fine wires. Effective characteristics of the pulse voltage, the pulse amplitude and the pulse width were found not depend on frequency of external magnetic field. Based on this phenomenon, a unique magnetic sensor was developed for a flow meter. In this study, the bilayered thin films with several different coercive forces and residual stresses were fabricated in order to simulate the Barkhausen effect in the thin film. As a result we observed a large Barkhausen jump in the bilayered film having the upper layer in tension and the lower layer in compression. The induced pulse voltages are not dependent on the external magnetic field frequency.

Magneto-impedance effect in etched thin amorphous wires

The magneto-impedance (MI) effect is investigated in etched thin zero-magnetostrictive amorphous wires having 4.5-30 /spl mu/m diameters. The MI effect gradually decreased with decreasing diameter and then the large Barkhausen effect appeared in thinner wires having 5-10 /spl mu/m diameters. Longitudinal BH loops are measured and estimated the average anisotropy direction in each etched wire considering the anisotropy energy change. A sensitive MI field sensor is constituted using the etched wire head having 16 /spl mu/m diameter and 0.7 mm length magnetized with a pulse current using CMOS multivibrator.

Magnetic behavior of nanostructured glass covered metallic wires

We present a study of the evolution of the magnetic properties and behavior of Fe73.5Cu1Nb3Si13.5B9 glass covered wires and wires after glass removal with the annealing temperature up to 600 °C starting from the amorphous state. The changes induced in the magnetic properties of these wires are determined by the stress relief process occurring at temperatures below 550 °C, and by the appearance of the nanosized α-FeSi crystalline grains after annealing for 1 h at 550 °C. The nanocrystalline phase formation leads to an improvement of the soft magnetic properties of these wires—increase of permeability and decrease of the coercive force—but also determines the disappearance of the large Barkhausen effect presented by these wires in the amorphous state. Annealing at temperatures over 550 °C determines a depreciation of the soft magnetic properties of both glass covered wires and wires after glass removal. The magnetic behavior of such wires can be fully explained by taking into account the relaxation of the internal stresses with increasing the annealing temperature as well as the changes in the magnetostriction constant due to the appearance of the nanocrystalline grains.

回転液中紡糸法によるFe-6.5 mass%Si繊維の紡糸条件と構造および磁気特性

Almost zero magnetostrictive Fe-6.5 mass%Si alloy fibers less than about 90 μm in diameter, having a large Barkhausen effect in magnetic properties were obtained by using the laboratory scale, the In-Rotating-Liquid-Spinning Process (INROLISP). The spinning conditions, jet stability, morphology of dendritic growth and magnetic properties were discussed for the fiber about 70 μm in diameter from the manufacturing viewpoint. In the case of spinning speeds of less than about 10 m/s, the jet bounced on the surface of rotating liquid, such as water, water with chemicals lowering surface tension, and some oils. Over 10 m/s, the jet subsequently penetrated under the liquid surface after an interval of around 100 ms from ejecting start. The centrifugal force effect was considered in this phenomenon. When the jet bounced, in some part of the fiber structure, primary dendrite arms growing uniformly along the fiber direction were observed. In another part, however, the direction of the primary arm changing gradually far from the fiber axis and the secondary arm becoming the primary grown to the fiber axis was observed without clear grain boundary. It is considered that the curvature of the bouncing jet at the ejection point obstructs the primary arms growing in a straight line. When jet penetrated, the “bamboo structure” was observed in the fiber structure. The penetrating jet formed the cavity of the coolant at its downstream from the jet. It means that the penetrating jet at first goes through the non-contacting area to the coolant at the cavity side and the contacting area to the coolant at the opposite side. Therefore, the primary arms tend to grow from the contact to the cavity sides. By the zone-annealing process, it was difficult to make any fiber a fairly long single crystal. In order to control the continuous growth of the primary arms toward the fiber direction, it was suggested that the process which is able to cool the jet uniformly around its circumference and make the primary arms grown in a straight jet is needed. The necessary conditions to produce a fiber having the large Barkhausen effect in this alloy, were the nearly unidimensional shape and a [100] crystal direction of arpha-phase parallel to the long axis. Furthermore, to obtain an ideal rectangular hysteresis loop, the cross-sectional round shape, the absence of residual stress and precipitation was suggested.

ガス中紡糸回転液中巻取法による結晶方位を制御したFe-6.5 mass%Si繊維の製造プロセス

Abstract A new process where a melt jet is quenched in gas followed by winding in a rotating liquid, which is a modified process of the in-rotating-water-spinning Process (INROLISP), has been developed in order to make continuous Fe–6.5 mass% Si alloy fiber with primary dendrite arms parallel to the fiber axis, having nearly zero magnetostriction. The molten alloy is ejected from a nozzle through a He gas zone located just under the nozzle, followed by an O 2 gas zone. He gas protects the orifice from plugging with metal oxides. The oxygen in the next zone forms a metal oxide sheath on the jet surface to restrain the jet from breaking up. The straight jet covered with oxide film continuously solidified and caused recalescence. After the recalescence the fiber was wound in a rotating liquid. Without the oxidization zone, such as only He or only NH 3 vapor, the jet was more rapidly cooled but became fractured. In case of CO 2 in the oxidization zone, the jet became fractured and led to short fibers. The capillary breakup length of a jet ( L BU ) can be calculated by L BU = K · V ·( ρ · d 3 / γ ) 1/2 , where V is mean velocity of a jet, ρ the density of the molten alloy, d the diameter of nozzle, and γ the surface tension of the molten alloy. In this work, the coefficient K was estimated as 10–20 from the experimental results for the He zone length and the velocity of the jet. The spinning gap between the nozzle exit and the rotating liquid surface was set 0.2–1.0 m which is longer than the length between the nozzle exit and the start of recalescence. Fibers about less than 100 μm in diameter, longer than 10 m in length, having a large Barkhausen effect were obtained.

Effect of Mn, Sn, and Cr additions on the magnetic properties of the amorphous glass-covered wires from the Fe-Si-B system

Results on the effect of Mn, Sn, and Cr additions on the magnetic properties of positive magnetostrictive Fe/sub 79/Si/sub 5/B/sub 16/ amorphous glass-covered magnetic wires are presented. Magnetic measurements performed on Fe/sub 75/Si/sub 5/B/sub 16/Mn/sub 4/, Fe/sub 77/Si/sub 5/B/sub 16/Sn/sub 2/, and Fe/sub 77/Si/sub 5/B/sub 16/Cr/sub 2/ amorphous glass-covered wires show the existence of a large Barkhausen effect in these wires, but the switching fields are smaller than those of the Fe/sub 79/Si/sub 5/B/sub 16/ ones. These additions also diminish the saturation magnetization of FeSiB amorphous glass-covered wires. Measurements on samples after glass removal have been also performed. The results are interpreted by taking into account the reduction in the strength of the magnetoelastic coupling between internal stresses and magnetostriction due to the decrease of the magnetostriction constant.

Phase Modulation Device Using Amorphous Short Wire

A new phase-modulation device with simple structure and high reliability was constructed using a short amorphous wire. A high-frequency ac current (carrier) and a signal current are simultaneously passed through the wire, which undergoes the large Barkhausen effect when the circumferential flux changes. Highly linear modulation characteristics were obtained up to 0.6π using a triangular-wave ac current, passed through tension-annealed wire 30 μm in diameter and 5 mm in length. This simple yet reliable phase modulation device is expected to find applications in the field of factory automation communication networks.