Amorphous Ferromagnetic Ribbons Research Articles

Influence of magnetic relaxation on magnetoelastic resonance-based detection

The phenomenon of magnetic relaxation in amorphous ferromagnetic alloys can result in an undesired time evolution of the magnetization that produces serious drawbacks in the use of these materials in sensor applications. The present work studies, at room temperature, the influence of magnetic relaxation on the performance of an amorphous ferromagnetic ribbon as the main element of a magnetoelastic resonance (MER)-based sensor. The time evolution was observed through the evolution of the MER signal, in particular through the variation experienced by the resonance frequency , which is the main parameter used for sensing. It is found that, after the bias field is changed to a given value, and under constant excitation conditions, increases with time in a typical relaxation behavior with a relaxation amplitude and a relaxation time that depend on the excitation conditions. The amplitude of the excitation h turned out to be a key factor on the relaxation, since larger excitation field amplitudes (h mOe) result in a considerable decrease of relaxation times ( and a reduction of the variation of the resonance frequency (). The influence of this relaxation on the sensor performance and the possible approaches to overcome this problem are evaluated and applied to the case of a magnetoelastic sensor, operating as mass sensor, for monitoring a chemical precipitation reaction.

Detection of Diazinon Organophosphates Using Magnetoelastic Sensor

In this study, 2826MB (Fe₄₀Ni₃₈Mo₄B₁₈) amorphous ferromagnetic ribbons were used as a magnetoelastic sensor (MES) to detect diazinon organophosphates (OP). Since enlarging the sensor surface area makes a significant contribution to the sensitivity of the sensor, nanofibers were coated on the sensor surface, and then, the nanofibers were functionalized with glutaraldehyde (GA) in order to covalently bind acetylcholinesterase (AChE) enzyme to the surface. It was found that binding of OPs to the AChE enzyme at the functional amorphous ribbon surface, a large change in the resonance frequency was observed. The results showed that functionalized MES shows a linear change according to the amount of OP detected in the range of 0–140 nL or 0–150 ppm in the solution.

Magnetoelastic Humidity Sensors with TiO2 Nanotube Sensing Layers.

In this study, TiO2 nanotubes (TiO2-NTs) are coated with a drop-casting method on Fe40Ni38Mo4B18 amorphous ferromagnetic ribbons and the humidity response of the prepared magnetoelastic sensors (MES) is investigated. The synthesis of TiO2-NTs is performed using a hydrothermal process. Sample characterization is carried out using X-ray diffraction and scanning electron microscopy. The results show that the sensors can measure moisture values in the range of 5% to 95% with very high precision and very low hysteresis. The humidity variation between 5% and 95% shows a change in the sensor resonance frequency of ~3180 Hz, which is a significant change compared to many magnetoelastic humidity sensors developed so far.

Observation of the inverse magnetoelectric effect in PZT/FeCuNbSiB two-layered composite structures

In recent years, much attention has been paid to the study of magnetoelectric (ME) effects in solids, which was caused by their potential practical applications. Of particular interest are composite multiferroic materials containing ferroelectric and ferromagnetic phases, since significant ME responses may occur in them. This paper is devoted to the study of the inverse ME effect in a two-layered composite sample consisting of a piezoelectric Pb(Zr, Ti)O3 (PZT) plate and an amorphous FeCuNbSiB ferromagnetic ribbon. It was found that the inverse ME effect depends on the magnitudes of the external magnetic field H, the electric voltage U and on the mutual orientation of H and U.

Formation and Detection of Magnetic CoNiFe Nanowire Network Using Magnetoelastic Sensor

In this study, CoNiFe magnetic nanowires were detected using a magnetoelastic sensor (ME) without any coating. Amorphous ferromagnetic ribbon of Metglass 2826 (Fe40Ni38Mo4B18) was used as a magnetoelastic sensor. The magnetoelastic ribbons were drop coated with Co12Ni64Fe24 magnetic nanowires in order to study how the mass deposition affects the resonance frequency and to determine the amount of coated nanowire. It was found that the minimum amount of detected nanowire can be as low as 200 ng. It was also shown that the nanowire network was developed on the surface of Metglass 2826 MB magnetoelastic sensor.

Tensductor-Amorphous Alloy Based Magnetoelastic Tensile Force Sensor.

In this paper new, tensile force sensor is presented, based on Pressductor topology and single layer of ferromagnetic amorphous ribbon. Simplified operating principle of the magnetic core with orthogonal coils is described. Straight and diagonal cut sensors are compared. The load vs. induced voltage characteristics are presented, as well as possibility of higher harmonics utilization. The effect of supply current on signal amplitude and measurement hysteresis is given. The developed ‘Tensductor’ sensor has near-linear characteristics and is relatively easy to manufacture. The measurement range is scalable, the experimental unit had 0–12 N measurement range with 1% accuracy, mostly due to magnetoelastic hysteresis.

Magnetoelectric coupling of a magnetoelectric flux gate sensor in vibration noise circumstance

A magnetoelectric (ME) flux gate sensor (MEFGS) consisting of piezoelectric PMN-PT single crystals and ferromagnetic amorphous alloy ribbon in a self-differential configuration is featured with the ability of weak magnetic anomaly detection. Here, we further investigated its ME coupling and magnetic field detection performance in vibration noise circumstance, including constant frequency, impact, and random vibration noise. Experimental results show that the ME coupling coefficient of MEFGS is as high as 5700 V/cm*Oe at resonant frequency, which is several orders magnitude higher than previously reported differential ME sensors. It was also found that under constant and impact vibration noise circumstance, the noise reduction and attenuation factor of MEFGS are over 17 and 85.7%, respectively. This work is important for practical application of MEFGS in real environment.

Magnetoelastic Resonators for Highly Specific Chemical and Biological Detection: A Critical Study

We have developed a detection system made of an amorphous ferromagnetic ribbon of composition Fe64Co17Si6.6B12.4, with excellent magnetoelastic properties as a saturation magnetostriction of 23 ppm and a $\Delta E$ effect of 27%. The resonators were coated with polystyrene (PS). Consecutive depositions were applied by dip coating from 10 to $100~\mu \text{M}$ solution in tetrahydrofuran. The mass increment after each deposition was accurately measured with a high precision (0, $1~\mu \text{g}$ ) balance and was compared with the corresponding resonant frequency. We have tested resonators with $L = 3$ , 2, and 1 cm length. As theory predicts, we have observed a decrease in the resonant frequency as the PS mass increases, reaching a maximum sensitivity of $S = \Delta f/\Delta m = 52.4$ Hz/ $\mu \text{g}$ (that corresponds to 19 ng detection for 1 Hz resolution), for the 1 cm length resonator. Nevertheless, our measurements show even better results than theoretically predicted by the common resonator model. Bearing this in mind, here, we present a critical study on the conditions for optimum performance of such resonance-based sensing devices, both from the point of view of the magnetoelastic resonance conditions and from the layer deposition procedure.

Magnetoimpedance exchange coupling in different magnetic strength thin layers electrodeposited on Co-based magnetic ribbons

A systematic study of the effect of the deposition of cobalt (Co) and nickel (Ni) layers of various thicknesses on the magnetoimpedance (MI) response of a soft ferromagnetic amorphous ribbon (Co68.15Fe4.35Si12.5B15) is performed. The Co and Ni layers with thicknesses of 5, 10, 20 and 40 nm were grown on both sides of the amorphous ribbons by the electrodeposition technique. Microstrutures determined by x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) showed higher crystallinity of Ni-deposited layers and the amorphous ferromagnetic nature of Co-deposited. The vibrating sample magnetometry (VSM) does not represent significant changes between samples because of the small contribution of such a thin layer deposited on thick ribbons, but the MI response dictates that the magnetic coupling effect occurred at the interface of such bilayers, which is sensitive to the skin effect. The MI response of Co-deposited ribbons showed MI hysteretic behavior depending on the deposited layer thicknesses with an optimum response for the thickness of 20 nm whereas no hysteretic behavior was measured for Ni-deposited ribbons. This behavior is explained according to the exchange coupling between magnetization of electrodeposited layers and magnetic ribbons with respect to different magnetic properties of Co and Ni at different thicknesses. Also the MI response of Ni- and Co-deposited ribbons enhanced significantly at low thicknesses relative to bare ribbon. By increasing the thickness of deposited layers, MI response decreases considerably. Differences in MI ratios of Co- and Ni-deposited ribbons are explained according to exchange length, crystallinity and roughness of deposited layers. Our results could address a simple way to achieve a higher MI response, and explains physical aspects of exchange coupling in MI response all towards a better performance of magnetic field sensors.

Magneto-reactance based detection of MnO nanoparticle-embedded Lewis lung carcinoma cells

We demonstrate the capacity of detecting magnetically weak manganese oxide (MnO) nanoparticles and the Lewis lung carcinoma (LLC) cancer cells that have taken up these nanoparticles using a novel biosensor based on the magneto-reactance (MX) effect of a soft ferromagnetic amorphous ribbon with a microhole-patterned surface. While the magnetic moment of the MnO nanoparticles is relatively small, and a magneto-impedance based sensor fails to detect them in solution (0.05 mg/ml manganese oxide lipid micellar nanoparticles) and inside cells at low concentrations (8.25 × 104 cells/ml), the detection of these nanoparticles and the LLC cells containing them is achieved with the MX-based sensor, which, respectively, reaches the detection sensitivity of ∼3.6% and 2.8% as compared to the blank cells. Since the MnO nanoparticles are a promising contrast agent for magnetic resonance imaging (MRI) of lung cells, the MX-based biosensing technique can be developed as a pre-detection method for MRI of lung cancer cells.

Magnetic and screening properties of amorphous ferromagnetic ribbons

We have studied the magnetic and screening properties of cylindrical shields made of amorphous ferromagnetic ribbons. It is established that the relative magnetic permeability of this material can exceed 106. The action of an alternating decaying magnetic field (demagnetization) converts amorphous ferromagnetic ribbons into the state of anhysteretic magnetization, which is characterized by extremely high (above 2 × 107) values of the relative magnetic permeability in magnetic fields at a level of 10 nT. The results of measurements were used to estimate the coefficient of attenuation of the Earth’s magnetic field inside cylindrical shields with open ends, depending on the diameter and the number of layers of an amorphous ferromagnetic ribbon.

Impacts of amorphous and crystalline cobalt ferrite layers on the giant magneto-impedance response of a soft ferromagnetic amorphous ribbon

A systematic study of the effect of depositing CoFe2O4 (CFO) films of various thicknesses (d = 0–600 nm) on the giant magneto-impedance (GMI) response of a soft ferromagnetic amorphous ribbon Co65Fe4Ni2Si15B14 has been performed. The CFO films were grown on the amorphous ribbons by the pulsed laser deposition technique. X-ray diffraction and transmission electron microscopy revealed a structural variation of the CFO film from amorphous to polycrystalline as the thickness of the CFO film exceeded a critical value of 300 nm. Atomic force microscopy evidenced the increase in surface roughness of the CFO film as the thickness of the CFO film was increased. These changes in the crystallinity and morphology of the CFO film were found to have a distinct impact on the GMI response of the ribbon. Relative to the bare ribbon, coating of amorphous CFO films significantly enhanced the GMI response of the ribbon, while polycrystalline CFO films decreased it considerably. The maximum GMI response was achieved near the onset of the structural transition of the CFO film. These findings are of practical importance in developing high-sensitivity magnetic sensors.

Resonance electromagnetoacoustic method of measuring viscoelastic properties of amorphous ferromagnetic ribbons subjected to low-temperature annealing

Stationary and damped vibrations of the s0 Lamb mode in a viscoelastic amorphous ferromagnetic ribbon excited upon the electromagnetoacoustic (EMA) transformation have been considered. A resonance method is suggested that employs double EMA transformation for measuring elasticity moduli E and internal friction in amorphous ferromagnetic ribbons. The effect of low-temperature isochronous annealing on the field dependences of Young’s modulus and internal friction of the Fe80Si10B10 and Fe73.7Cu1.0Nb3.2Si12.7B9.4 alloys has been studied.

Magnetoimpedance-Based Probe of Various Concentrations of Corrosive Chemicals

We report on the possibility of exploiting the giant magnetoimpedance (GMI) effect of a soft ferromagnetic amorphous ribbon as a magnetic label-free probe of corrosive strengths of chemicals. Scanning electron microscopy, dc magnetization, and GMI measurements reveal that the presence of nitric acid $({\rm HNO}_{3})$ significantly alters the surface morphology, the magnetic permeability, and consequently the GMI response of a ${\rm Co}_{65}{\rm Fe}_{4}{\rm Ni}_{2}{\rm Si}_{15}{\rm B}_{14}$ amorphous ribbon. With an increase in the exposure time, the GMI ratio sharply decreases in the first few minutes and then remains almost unchanged. The relative change in the GMI ratio depends strongly on the corrosive strength of the chemical used (i.e., the concentration of ${\rm HNO}_{3}$ ). These findings are of practical importance in developing GMI-based detectors of corrosive chemicals.

Laser assisted crystallization of ferromagnetic amorphous ribbons: A multimodal characterization and thermal model study

This paper focuses on laser-based de-vitrification of amorphous soft magnetic Fe-Si-B ribbons and its consequent influence on the magnetic properties. Laser processing resulted in a finer scale of crystallites due to rapid heating and cooling during laser annealing compared to conventional furnace annealing process. A significant increase in saturation magnetization is observed for laser-annealed ribbons compared to both as-received and furnace annealed samples coupled with an increase in coercivity compared to the as received samples. The combined effect of thermal histories and stresses developed during laser annealing results in the formation of nano-crystalline phase along the laser track. The phase evolution is studied by micro-XRD and TEM analysis. Solute partitioning and compositional variation within the phases are obtained by Local Electrode Atom probe analysis. The evolution of microstructure is rationalized using a Finite Element based heat transfer multi-physics model.

Enhanced electrical manipulation of magnetic susceptibility in ferromagnetic amorphous alloy and piezoelectric bimorph heterostructure

In this study, we report an enhanced electrical manipulation of magnetic susceptibility in ferromagnetic amorphous alloy ribbon using a piezoelectric bimorph actuator. Theoretically, the strain produced by the piezoelectric bimorph and then coupled into the amorphous alloy ribbon is larger than that of a single piezoelectric plate under an identical applied electric field, thus resulting in a stronger magnetoelectric (ME) coupling for electrically manipulating magnetic susceptibility. Our experimental results have shown that the initial susceptibility tunability of the amorphous alloy ribbon upon the tuning electric field applied on the piezoelectric bimorph ranging from 0 kV/cm to 5 kV/cm can reach up to 750% at low-frequency of 1 kHz and maintain 80% at 1 MHz. This study expands the structure design of ME smart devices, especially the electrically controllable magnetic devices.

Enhanced giant magneto-impedance effect in soft ferromagnetic amorphous ribbons with pulsed laser deposition of cobalt ferrite

We have grown a 50 nm thick magnetic layer of cobalt ferrite (CFO) on two Co-based amorphous ribbons of compositions Co65Fe4Ni2Si15B14 (type I) and Co69Fe4Ni1Mo2B12Si12 (type II) by a pulsed laser deposition technique. A comparative study of the influence of this CFO layer on the giant magneto-impedance (GMI) effect and field sensitivity (η) of the ribbons is presented. Our results reveal that the presence of the CFO layer enhanced both the GMI ratio and the field sensitivity of the ribbons. Relative to the plain ribbons, the GMI ratio and field sensitivity of the CFO-coated ribbons increased by 97% and 42% for type I and by 34% and 50% for type II, respectively. The enhanced effects are attributed to the modifications on the ribbon surface and closure of magnetic flux paths due to the CFO layer.

Detection of low-concentration superparamagnetic nanoparticles using an integrated radio frequency magnetic biosensor

Improving the sensitivity of existing biosensors for highly sensitive detection of magnetic nanoparticles as biomarkers in biological systems is an important and challenging task. Here, we propose a method of combining the magneto-resistance (MR), magneto-reactance (MX), and magneto-impedance (MI) effects to develop an integrated magnetic biosensor with tunable and enhanced sensitivity. A systematic study of the 7 nm Fe3O4 nanoparticle concentration dependence of MR, MX, and MI ratios of a soft ferromagnetic amorphous ribbon shows that these ratios first increase sharply with increase in particle concentration (0–124 nM) and then remain almost unchanged for higher concentrations (124 nM–1240 nM). The MX-based biosensor shows the highest sensitivity. With this biosensor, ∼2.1 × 1011 7 nm Fe3O4 nanoparticles can be detected over a detection area of 2.0 × 105 μm2, which is comparable to a superconducting quantum interference device biosensor that detects the presence of ∼1 × 108 11 nm Fe3O4 nanoparticles over a detection area of 6.8 × 104 μm2. The proposed biosensor can detect low and various concentrations of superparamagnetic nanoparticles (below 10 nm in size), which is of practical importance in biosensing applications.

Structure analysis of CoFeBSiNb(Ga) pseudobulk metallic glasses

Rapidly quenched Co–Fe based ferromagnetic amorphous ribbons and pseudobulk metallic glasses are attractive group of materials for structural and functional use. In the present contribution, structure of as-cast and annealed Co–Fe–B–Si–Nb pseudobulk metallic glasses with increased thickness was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In addition, influence of a small addition of gallium (2 at.%) into base composition on structure of the ribbon was investigated.

Relaxation studies of amorphous alloys with creep induced magnetic and structural anisotropy

Amorphous ferromagnetic (Fe,Co,Ni) ribbons of various compositions have been prepared by rapid solidification and annealed with applied tensile stress. This process yields both creep-induced magnetic anisotropy and structural anisotropy. Post-annealing has been done to investigate the relaxation process. X-ray diffraction and thermomechanical analysis measurement of post-annealed samples reveal a clear underlying relaxation process in the material, proving that structural anisotropy corresponds to the elastic strain induced by creep annealing.