Stress-impedance Effect Research Articles

Pressure stress-impedance effect in FeCuNbSiB amorphours ribbons

The stress-impedance effect in Fe73.5Cu1Nb3Si13.5B9 (at%) ribbons is measured to investigate the influences of vacuum annealing and pressure stress. The results can be explained by the influence of induced anisotropy in the magnetization processes at the chosen drive current frequency of 90 MHz. The maximum S/% value of the ribbon annealed at 300°C is 2.52%.

Stress impedance effects in flexible amorphous FeCoSiB magnetoelastic films

Amorphous FeCoSiB films were deposited on the flexible polyimide substrates (Kapton type (VN)) by DC magnetron sputtering. Stress impedance (SI) effects of the flexible amorphous FeCoSiB magnetoelastic films were investigated in details. The results show that a large stress impedance effect can be observed in the flexible amorphous FeCoSiB magnetoelastic films. And the results also show a bias magnetic field plays an important role in the stress impedance of FeCoSiB films. Applied a bias magnetic field during depositing can induce obvious in-plane anisotropy in the FeCoSiB films, and a larger SI effect can be obtained with a stronger anisotropy in FeCoSiB films. Argon pressure has a significant effect on the SI effect of the FeCoSiB films. The SI of the FeCoSiB films reaches a maximum of 7.6% at argon pressure of 1.5 Pa, which can be explained by the change of residual stress in FeCoSiB films.

The influence of anisotropic fields on stress-impedance effect in amorphous alloys

The theory of stress-impedance effect in amorphous alloys was established by introducing stress-induced anisotropy and magnetic anisotropy and solving Maxwell's equations and Landau-Lifshitz equation with the Gilbert term. The established theory can be used to explain the stress-impedance effect, and the calculation results were in good agreement with the experimental results. We calculated the stress-impedance change with different anisotropy parameters, and reached important conclusions both in theory and for applications.

Simulation of stress-impedance effects in low magnetostrictive films

A theoretical study of stress-impedance effect based on the solution of Landau–Lifsitz–Gilbert equation has been carried out. The results show that stress impedance effects depend largely on several extrinsic (external bias field, external frequency) and intrinsic (orientation and magnitude of uniaxial anisotropy, damping) parameters.

Induced Magnetic Anisotropy and Stress-Impedance Effect in Nanocrystalline$hboxFe_73.5hboxCu_1hboxNb_3hboxSi_13.5hboxB_9$Ribbons

The influence of direction and strength of induced magnetic anisotropy on stress-impedance (SI) effect was experimentally and theoretically studied in this paper. Experimentally, it was found that the magnetic anisotropy of the stress Joule heated Fe73.5Cu 1Nb3Si13.5B9 nanocrystalline ribbons were determined by direction and strength of the induced anisotropy. Theoretical calculations of the direction and strength of the induced magnetic anisotropy suggest that transverse anisotropy and small anisotropic field result in an increase of the SI effect. To decrease the anisotropic field and increase the transverse anisotropy simultaneously, a complex annealing process was applied to Fe73.5 Cu1Nb3Si13.5B9 ribbons, and it was found that the SI effect was drastically improved. A maximum change of 286% in the SI ratio of the complex annealed nanocrystalline Fe73.5Cu1Nb3Si13.5 B9 ribbon was observed around 10 MHz frequencies

Giant Stress-Impedance Effect in Co71.8Fe4.9Nb0.8Si7.5B15 Glass-Covered Amorphous Wires

The giant stress-impedance (GSI) effect in as-cast and DC current annealed Co71.8Fe4.9 Nb0.8Si7.5 B15 amorphous glass-covered wires is presented. The SI ratio of the as-cast sample exhibits negative GSI effect. For the sample annealed by 60 mA DC current, the SI ratio first increases with applied tensile stress, then decreases. The maximum ΔZ/Z ratio of 304% is obtained. Frequency dependence in the range from 1 to 110 MHz of the GSI effect is investigated. Experimental results show that the real part R and the imaginary part X of impedance play an important role at high frequency and low frequency, respectively. At 1 MHz, the maximum ΔX/X ratio of 1 448% is obtained. At 110 MHz, the maximum ΔR/R ratio of 648% is obtained.

Torsional stress impedance effect in Fe 71 Cr 7 Si 9 B 13 amorphous wire

The magnetoimpedance effect has been measured in as-received and current annealed Fe71Cr7Si9B13 amorphous wires under torsional stress varied up to 1.2 rad/cm. It was found that the torsional stress dependence of impedance of as-received amorphous wire has a non-monotonous shape with first an increase of the impedance and then a decrease. On the other hand, the impedance of current annealed wire directly starts to decrease with increasing torsional stress. The current annealing of wire results in a large variation in the magnitude of torsional stress impedance effect, (ΔZ/Z)ξ(%), up to 150%. Also, a simple mathematical model based on the magnetic moment rotation to explain torsional stress versus impedance data was developed and the results were partly discussed on the basis of this model. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Simulation of stress impedance effect in magnetoelastic films

Extensive studies have been conducted in magnetoelastic films because of its application in stress sensors based on the stress impedance effect. In this paper, the stress impedance effects have been studied based on the Landau–Lifshitz–Gilbert equation. The results show that the stress impedance effects are strongly dependent on the thickness of the magnetoelastic film, the residual stress and the uniaxial magnetic anisotropy.

Giant stress-impedance effect in Fe 71Cr 7Si 9B 13 amorphous wires

The giant stress-impedance (SI) effect in as-received and furnace annealed Fe 71Cr 7Si 9B 13 amorphous wires is studied. Samples were annealed at temperature of 460 °C for times between 0.3 and 300 min to remove internal stresses. The results show that the magnetoimpedance and SI effect change sharply with annealing and a maximum stress-impedance ratio of 255% is observed in the wire annealed for 10 min under an applied tensile stress of 250 MPa.

Magnetic anisotropy and stress-impedance effect in Joule heated Fe73.5Cu1Nb3Si13.5B9 ribbons

The stress-impedance (SI) profiles were measured in Fe73.5Cu1Nb3Si13.5B9 ribbons annealed by Joule heating in the presence of longitudinal applied tensile stress of 100 MPa and the maximum SI ratio of 350% is observed. It was found that the large SI effect is the result of induced transverse magnetic anisotropy. We present a model that explains the variations of transverse magnetic anisotropy on SI effect. The model is based on the skin effect and on the magnetization rotation due to the applied tensile stress and the ac driving current.

Giant stress-impedance effect in amorphous and thermally annealed Fe73.5Cu1Nb3Si13.5B9 ribbons

A giant stress-impedance (GSI) effect with a strain gauge factor of more than 5000 was observed in initially amorphous Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 ribbons annealed at 600 °C for 30 min. The components of resistance R and reactance X of the complex impedance Z = R + iX , as well as the relative effective permeability μ eff , for as-quenched and thermally annealed Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 ribbons have been studied as functions of longitudinal applied tensile stress. The reactance X dominates the GSI effect and a maximum GSI ratio of 25% is observed for the sample annealed at 600 °C for 30 min. The effective permeability has been shown to be responsible for the GSI effect.

Giant stress-impedance effect in Fe 73.5CuNb 3− xV xSi 13.5B 9 amorphous ribbons

In the present work, the giant stress-impedance effect in Fe 73.5CuNb 3Si 13.5B 9 and Fe 73.5CuNb 2VSi 13.5B 9 amorphous ribbons was reported. The stress-impedance Δ Z/ Z 0 decreases with increasing ac frequency from 100 kHz to 20 MHz. When tensile stresses are applied perpendicular to the Earth's field, the value of stress-impedance Δ Z/ Z 0 at 100 kHz can reach –9.9% under a stress of 24.6 MPa for Fe 73.5CuNb 3Si 13.5B 9 ribbon, and –22.4% under a stress of 84.8 MPa for Fe 73.5CuNb 2VSi 13.5B 9 ribbon. The stress-impedance effect becomes small when tensile stresses are applied parallel to the Earth's field. The stress-impedance effect may be connected with the variation of the magnetic domain and permeability under application of stresses.

Giant Stress-Impedance Effect in Amorphous andHigh-Current-Density Electropulsing AnnealedFe73.5Cu1Nb3Si13.5B9 Ribbons

The stress-impedance (SI) effect has been observed in as-cast andhigh-current-density electropulsing annealedFe73.5Cu1- Nb3Si13.5B9 ribbons. Large SI ratios of-35% and 25% have been obtained in high-current-density electropulsingannealed samples but not in as-cast samples. The SI effect changesdrastically with the density of the annealing current and the longitudinally appliedstress during the annealing process. The effective permeability has beenshown to be responsible for the SI effect.

Large stress-resistance effect at high frequencies in Co68.5Fe4.5Si12B15amorphous ribbon

In the present work, the stress-impedance and the stress-resistance for Co 68.5 Fe 4.5 Si 12 B 15 amorphous ribbon are reported. The stress-impedance decreases with increasing tensile stress. In contrast, the large stress-resistance appears at high frequency. The value of with F = 20 g can reach 31.4% at 5 MHz. The mechanism of the stress-impedance effect is also discussed.

Giant stress-impedance effect in amorphous and current annealed Fe 73.5Cu 1Nb 3Si 13.5B 9 wires

The giant stress-impedance (GSI) effect in Fe 73.5Cu 1Nb 3Si 13.5B 9 wires is measured to investigate the influence of Joule heating and pulse current annealing as well as tensile stress applied during the annealing process on it. The results show that the GSI effect changes drastically with annealing techniques and the maximum stress-impedance ratio of 80% is obtained at 5.5 MHz under applied tensile stress of 20 MPa.

アモルファス磁歪ワイヤＳＩ効果形毛根式気流センサ素子

A sensitive air-flow sensor element was constructed, using an arched CoSiB magnetostrictive amorphous wire connected to a straight hair-type amorphous wire. A sharp pulse current is applied through the arched wire to generate the stress-impedance (SI) effect with a strong skin effect. The resolution for air flow detection is about 0.16 m/s, which is almost the same as that of conventional heated resistance wire-type air-flow sensors. The amorphous wire air-flow sensor element is suitable for adding an air-flow-sensing ability to intelligent robots.

アモルファス負磁歪ワイヤのひねり応力‐インピーダンス効果

A sensitive twisting stress-impedance effect in a CoSiB amorphous wire (λ= -3 × 10-6, 20 μm diameter, 10 mm length) is presented. The impedance in the wire changes by more than 50% for a twisting angle of ± 180°(1/2 turn). The impedance change occurs with the skin effect in the wire, and its twisting characteristic depends on the wire current frequency. The mechanisms of the twisting stress-impedance effect is analyzed, taking account of BH hysteresis loops in the wire’s circumferential flux path and a magnetization rotation model.

Sensitive Strain Gauge Using a CMOS IC Combined with an Amorphous Magnetostrictive Wire Cantilever Beam

A highly sensitive linear strain gauge using a pair of amorphous CoSiB wires fixed to a plastic cantilever beam combined with a CMOS IC multivibrator circuit is presented. The wires are magnetized with a sharp pulse current to generate the stress impedance (SI) effect, showing a gauge factor of about 2000 in the CMOS IC circuit The linear strain gauge shows a resolution of about 2.5 mg for weight detection with high linearity in the range of −0.75∼1.25 g. The mechanism of the SI characteristics in the CoSiB wire is analyzed using a magnetization rotation model. Pulsation of fingertip blood vessels was stably detected by using the SI gauge stress sensor.

Sensitive stress-impedance micro sensor using amorphous magnetostrictive wire

A giant stress-impedance (GSI) effect with the strain-gauge factor more than 1200 was found in negative magnetostrictive amorphous CoSiB wires of 30-/spl mu/m diameter magnetized with a high frequency current or a sharp pulse current. A sensitive stress sensor is constructed using a CMOS IC multivibrator circuit in which the amorphous wire is magnetized with a sharp pulse train current. The amorphous wire GSI sensor will be applied for detection of such as pressure, tension, stream speed for liquid and gases and mechano-cardiogram with the sensitivity of 5-6 times higher than that of the semiconductor stress sensors utilizing the piezo-resistance effect showing a gauge factor of about 200.