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Öğe Amorphous ferromagnetic wire for manipulation of magnetic nanowires(Elsevier Science Sa, 2015) Atalay, S.; Atalay, F. E.The article reports the development of new type of magnetic tip to manipulate magnetic nanowires. The amorphous ferromagnetic tip has a composition of Fe77.5Si7.5B15. Electrochemical etching was performed at room temperature for various dc currents up to 5 mA. It was found that 4.4 mA etching current was the best tip formation current for the FeSiB wire. It was found that the tip radius is smaller than 200 nm after the etching process. Magnetic NiFe nanowires were manipulated using a 3D positioning system with the FeSiB tip. (C) 2015 Elsevier B.V. All rights reserved.Öğe Characterisation of magnetic wires for fluxgate cores(Elsevier Science Sa, 2008) Ripka, P.; Butta, M.; Malatek, M.; Atalay, S.; Atalay, F. E.Orthogonal fluxgate sensors need only a single core and they can be made very small. We show how to measure properties of composite Cu/Py ferromagnetic wires to be used as cores for these sensors. Besides the well known axial loops we show how to measure the circumferential hysteresis loop and gating curves, which can directly be used for sensor modeling. It is generally believed that in composite wires the majority of the current flows through the copper core, thus reducing the possible perming effect of poorly magnetized core sections. We will show that this is true only at very low frequencies and for low magnetic layer thickness. The calculated values can be used as a starting point for FEM simulations. (c) 2007 Elsevier B.V All rights reserved.Öğe Coil-less Fluxgate Effect in Amorphous Co71Fe1Mo1Mn4Si14B9 Ribbon(Trans Tech Publications Ltd, 2012) Fidan, A.; Atalay, S.; Bayri, N.; Atalay, F. E.; Yagmur, V.In this study, the coil-less fluxgate effect in Co71Fe1Mo1Mn4Si14B9 amorphous ribbon was investigated. The coil-less fluxgate is a new type of fluxgate sensor without a coil. It is based on helical anisotropy and deep circumferential magnetic saturation in the ferromagnetic fluxgate core. Coil-less fluxgate measurements were performed in as-cast and annealed ribbons at 480 mA current with 3, 12.5 and 25 rad/m torsion. The second harmonic of the output voltage detected from the ends of the wire show a linear variation in the low magnetic field region. The sensitivity of the current annealed ribbons in the presence of 25 rad/m torsion is about 570 V/T, which is comparable with previously reported fluxgate sensitivity values. The presented sensor has no coil so it is much easier to reduce the size of the sensor and easy to fabricate it.Öğe Coil-less fluxgate effect in amorphous wires(Elsevier Science Sa, 2010) Atalay, S.; Bayri, N.; Izgi, T.; Atalay, F. E.; Kolat, V. S.In this study, the coil-less fluxgate properties of as-received amorphous microwires with the compositions (Co(0.94)Fe(0.06))(72.5)Si(12.5)B(15), Fe(77.5)Si(7.5)B(15) and Co(72.5)Si(12.5)B(15) have been investigated. As its name implies, a coil-less fluxgate is a new type of magnetic field sensor without a coil. When the (Co(0.94)Fe(0.06))(72.5)Si(12.5)B(15) wire is magnetically saturated in the circumferential direction with a 30 kHz and 48 mA driving current and under the effect of 33 pi rad/m torsional strain, there is a linear variation in the second harmonic of the voltage from wire ends, U(wire) as a function of the applied external dc magnetic field, H(z), along the wire length. The slope of the second harmonic versus H(z) curve changes in opposite directions as the direction of torsional strain changes from the positive to the negative direction. Coil-less fluxgate effects in as-received Fe(77.5)Si(7.5)B(15) and Co(72.5)Si(12.5)B(15) wires have also been investigated. A very small change in the second harmonic of voltage U(wire) is observed in Fe(77.5)Si(7.5)B(15) wire, with some small hysteresis. (C) 2010 Elsevier B.V. All rights reserved.Öğe Coil-less fluxgate effect in CoNiFe/Cu wire electrodeposited under torsion(Elsevier, 2011) Atalay, S.; Yagmur, V.; Atalay, F. E.; Bayri, N.Co19Ni49.6Fe31.4 layer was electrodeposited onto a twisted Cu wire and helical anisotropy was induced in the magnetic Co19Ni49.6Fe31.4 shell. The magnetic and coil-less fluxgate (CF) properties are presented. The Co19Ni49.6Fe31.4/Cu wire, produced at zero torsional strain, shows a CF output of nearly zero. The samples produced under torsional strains of 29.5 pi and 59 pi rad/m show a linear change in CF output in the low-frequency range. At higher frequencies the CF output shows two linear ranges. A maximum sensitivity of 150V/T is observed at 20 kHz driving-current frequency and 67 mA driving current for a wire produced under 59 pi rad/m torsional strain. It is also found that the slope of the CF curve depends on the direction of induced anisotropy. (C) 2011 Elsevier B.V. All rights reserved.Öğe Coil-Less Fluxgate Effect in Negatively Magnetostrictive Co72.5Si12.5B15 Amorphous Wire(Amer Scientific Publishers, 2013) Atalay, S.; Bayri, N.; Fidan, A.; Yagmur, V.; Izgi, T.; Atalay, F. E.; Kolat, V. S.In this study, we have investigated coil-less fluxgate (CF) properties of as-cast and annealed Co72.5Si12.5.B15 amorphous wire. As-cast wire without any torsional strain shows nearly zero output in the second harmonic. When the as-cast wire is twisted a linear variation in the second harmonic of output was obtained as a function of applied magnetic field. It was also shown that a linear change in the output of the coil-less fluxgate sensor can be obtained using torsion annealed wire without twisting the wire during measurement. The second harmonic of U-wire showed a linear dependence at magnetic fields of +/- 400 A/m and the sensitivity of the sensor at 50 kHz frequency is about 75 V/T at 61 mA ac driving-current frequency for the wire annealed at 525 mA dc current for 20 minutes at 500 MPa tensile stress and 33 pi rad/m torsional strain.Öğe The Dynamic Effects in Electrodeposited NiFe/Cu Wire with Preliminary Torsion(Trans Tech Publications Ltd, 2012) Yagmur, V.; Atalay, F. E.; Bayri, N.; Atalay, S.Ni80Fe20/Cu composite wires were produced under torsion using electrodeposition method. The total length of the magnetic film deposited onto 50 mu m Cu wire is 3 cm and the thickness of the magnetic layer is about 10 gm. All samples showed single peak in magnetoimpedance (MI) curves. The magnitude (Delta Z/Z) % are 260%, 235% and 119% for samples produced under 22.4, 44.8, 89.7 rad/m torsion values, respectively at driving frequency of 160 kHz. MI effect magnitude decreases with increasing applied torsion during the electrodeposition process. A linear change in the second harmonics of output voltage from wire ends as a function of applied magnetic field (coil-less fluxgate effect) was observed in all sample. The sensitivity of coil-less output increases with increasing torsion and maximum sensitivity was observed in the sample produced at 89.7 rad/m torsion.Öğe The effect of back electrode on the formation of electrodeposited CoNiFe magnetic nanotubes and nanowires(Elsevier Science Bv, 2010) Atalay, F. E.; Kaya, H.; Yagmur, V.; Tari, S.; Atalay, S.; Avsar, D.The electrodeposition of cobalt + nickel + iron alloy nanostructures in aqueous sulfate solution has been studied using vitreous templates placed on highly ordered porous anodic alumina oxide (AAO). During the deposition process some electrochemical bath parameters such as ion content, deposition voltage, pH and temperature of solution were kept constant. The morphological properties of the nanostructures were studied by scanning electron microscopy (SEM) and the chemical composition was determined by examination of the energy dispersive X-ray (EDX) spectra. The magnetic behaviour of the arrays was determined with a vibrating sample magnetometer (VSM). Voltammetric and galvanostatic results indicate that the back electrodes placed on AAO plays the main role in obtaining nanowire or nanotube structured material. (C) 2009 Elsevier B. V. All rights reserved.Öğe Effect of tensile stress on magnetoimpedance properties of CoNiFe/Cu wire(Iop Publishing Ltd, 2009) Bayri, N.; Kolat, V. S.; Kaya, H.; Atalay, F. E.; Izgi, T.; Atalay, S.A Co20.5Ni40.5Fe39 magnetic film was electrodeposited onto a copper wire 50 mu m in diameter. The magnetoimpedance (MI) effect, (Delta Z/Z)(H)(%) = ((Z(H)-Z(max))/Z(max)) x 100, was measured in the Co20.5Ni40.5Fe39/Cu composite wire under varying tensile stresses up to 30 MPa. The results showed that large MI and stress impedance (SI) effects can be observed in the Co20.5Ni40.5Fe39/Cu composite wire. The MI curve at zero tensile stress shows a small split peak in the low-field region. With increasing applied tensile stress, single-peak behaviour of the MI effect is observed. The magnitude of the MI and SI effects decreases with increasing tensile stress, sigma. The peak values of (Delta Z/Z)(H)(%) for the sample decrease from 265% at sigma = 0 to 39% at sigma = 30MPa at 40 kHz ac driving-current frequency. The impedance of a sample under the effect of 25 MPa tensile stress at 40 kHz ac driving-current frequency showed variations of about 146%. It was also found that the frequency value, f*, where the maximum MI effect was observed as a function of driving-current frequency, increases with increasing tensile stress.Öğe Electrochemical Capacitance of Cobalt Oxide Nanotubes on Nickel Foam(Polish Acad Sciences Inst Physics, 2013) Yagmur, V.; Atalay, F. E.; Kaya, H.; Avcu, D.; Aydogmus, E.In this study, densely packed Co3O4 nanotubes for supercapacitors have been obtained by means of chemically depositing cobalt hydroxide within a porous anodic aluminum oxide and then annealed at 360 degrees C. The morphological properties obtained Co3O4 nanotubes were studied by scanning electron microscopy, the chemical composition was determined by examination of the energy dispersive X-ray spectra. Supercapacitor characteristics such as charging/discharging and impedance (Z) characteristics were also examined. DOI: 10.12693/APhysPolA.123.215Öğe The fabrication of metal oxide nanostructures using Deinococcus radiodurans bacteria for supercapacitor(Elsevier Sci Ltd, 2015) Atalay, F. E.; Asma, D.; Kaya, H.; Ozbey, E.The metal oxide nanostructures with high surface-to-volume ratio have been achieved using the Deinococcus radiodurans bacteria. In particular, the morphological properties of surface-layer proteins make them an ideal type of matrix for biotemplating the direct chemical synthesis of nanostructures. Surface properties of the metal-oxide nanostructures were investigated by electron microscopy. The surface area of that was also studied by Brunauer-Emmett-Teller (BET) analysis method. The materials were used at the construction of supercapacitor as electrode active materials. (C) 2014 Elsevier Ltd. All rights reserved.Öğe The Fabrication of NiO Microtubes Using Bacillus subtilis Bacteria(Polish Acad Sciences Inst Physics, 2014) Atalay, F. E.; Asma, D.; Aydogmus, E.; Turanci, H.; Kaya, H.The nickel oxide microtubes with high surface-to-volume ratio have been achieved using the Bacillus subtilis bacteria. Surface properties of the metal-oxide nanostructured materials were investigated by electron microscopy. The surface area of that was also studied by the Brunauer-Emmett-Teller analysis method. The materials were used at the construction of supercapacitor as an electrode active material.Öğe Fluxgate effect in twisted magnetic wire(Elsevier Science Bv, 2008) Butta, M.; Ripka, P.; Atalay, S.; Atalay, F. E.; Li, X. P.In this paper a novel kind of fluxgate is presented. The sensor is based on helical anisotropy of the ferromagnetic layer, electrodeposited on copper wire. The saturating field is provided by current. owing in the wire, and the output voltage is measured directly at the terminations of the wire. Therefore no coils are necessary, making possible high miniaturization of the sensor. The effect has been tested twisting the wire: the second harmonic is shown to be strongly dependent on the applied torsion. Consideration on the practical use of the sensors is finally presented. (c) 2008 Elsevier B.V. All rights reserved.Öğe Formation and Detection of Magnetic CoNiFe Nanowire Network Using Magnetoelastic Sensor(Springer, 2019) Atalay, S.; Kaya, H.; Atalay, F. E.; Izgi, T.; Kolat, V. S.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.Öğe The Formation of Free Standing NiO Nanostructures on Nickel Foam for Supercapacitors(Polish Acad Sciences Inst Physics, 2014) Atalay, F. E.; Aydogmus, E.; Yigit, H.; Avcu, D.; Kaya, H.; Atalay, S.In this study, free standing NiO nanostructures for supercapacitors were obtained by means of chemically depositing of nickel oxide on Ni foam and then they were annealed at various temperatures. The morphological properties of densely covered Ni foams were studied by scanning electron microscopy. Supercapacitor characteristics, such as charging/discharging and impedance characteristics, were also examined.Öğe Influence of the wire length on the of coil-less fluxgate properties of amorphous (Co0.94Fe0.06)72.5Si12.5B15 wire(Elsevier Science Sa, 2010) Atalay, S.; Bayri, N.; Izgi, T.; Yagmur, V.; Atalay, F. E.; Kolat, V. S.In this study, the coil-less fluxgate (CF) properties of amorphous (Co0.94Fe0.06)(72.5)Si12.5B15 wire, current-annealed at 450 mA dc for 15 min under 500 MPa tensile stress and 16.57 pi rad/m torsional strain, have been investigated. A CF is a new type of magnetic-field sensor without a coil. The dependence of the second harmonic of the output voltage from the wire ends, U-wire, on an external magnetic field in the longitudinal direction, H-z, for the frequency range 5-50 kHz and various values of the ac current I-wire is presented. The results show that the sensitivity of the CF depends on the frequency and I-wire. Even at a very low frequency (5 kHz). a pronounced variation in the behaviour of the CF sensor is observed. A 60-mm long sensor has a maximum sensitivity of 78.5V/T in a +/- 400 A/m linear operating range at 57 mA driving current. The sensitivity decreases but the linear operating range increases with decreasing wire length. A miniaturized 2.2-mm CF sensor shows similar to 0.4V/T sensitivity in a +/- 3000A/m linear operating range at 53 mA driving current and 50 kHz ac driving-current frequency. (C) 2010 Elsevier B.V. All rights reserved.Öğe La-Based Material for Energy Storage Applications(Polish Acad Sciences Inst Physics, 2017) Atalay, F. E.; Kaya, H.; Bingol, A.; Asma, D.In this work, nanostructured La-based materials were produced by chemical precipitation method onto Cladosporium cladosporioides fungal hyphae in aqueous solution. Materials were annealed at various temperatures between 100 degrees C-600 degrees C. The morphological properties of the synthesized material were studied by transmission electron microscopy. The surface area for sample annealed at 360 degrees C was determined to be 85.64 m(2)/g using Brunauer-Emmett-Teller method. The nitrogen adsorption and desorption isotherm displayed a typical type-IV isotherm. Electrochemical properties of produced material were studied using cyclic voltammetry, long term charge/discharge analysis and impedance spectroscopy in the 0.5 M Na2SO4 electrolyte. The obtained nanostructured porous electrode exhibits quasi-rectangular shaped cyclic voltammetry curves with a specific capacitance of 2190 F/g at a scan rate of 2 mV/s.Öğe Magnetic and magnetoimpedance properties of Mn-doped FINEMET(Elsevier Science Bv, 2009) Kolat, V. S.; Bayri, N.; Michalik, S.; Izgi, T.; Sovak, P.; Atalay, F. E.; Gencer, H.In this study, the effect of substituting Mn for Fe on the magnetic and magnetoimpedance (MI) properties of amorphous and nanocrystalline Fe73.5-xMnxCu1Nb3Si13.5B9 (x = 1, 3, 5, 7) alloys has been investigated. A higher Mn content causes a decrease in the saturation magnetization and Curie temperature. For as-received Fe73.5-xMnxCu1Nb3Si13.5B9 (x = 0, 1, 3, 5, 7) ribbons, the measured values of the MI are 11%, 12%, 16%, 12% and 15% for x = 0, 1, 3, 5, 7, respectively. The magnitude of the MI ratio increases in annealed samples, indicating that they are magnetically softened by nanocrystallisation. The change in MI is found to be similar to 70% for the x = 3 sample annealed at 550 degrees C. It is also found that replacing a small amount of Fe by Mn improves the magnetic softness of Fe73.5-xMnxCu1Nb3Si13.5B9 alloys. (C) 2009 Elsevier B.V. All rights reserved.Öğe Magnetoelastic sensor for magnetic nanoparticle detection(Elsevier Science Bv, 2018) Atalay, S.; Kolat, V. S.; Atalay, F. E.; Bayri, N.; Kaya, H.; Izgi, T.In this study, a magnetoelastic sensor (ME) without any coating was used to detect Fe3O4 magnetic nanoparticles (MNPs) for the first time in the literature. An amorphous 2605S3A (Fe77Cr2Si5B16) ribbon was used as an ME sensor, and samples were annealed in a furnace at 360 degrees C for 20 min to improve the ME response. A frequency shift of about 320 Hz was observed at 440 A/m magnetic field with the drop of 20 mu l MNPs on the surface of an amorphous ribbon. MNPs of 10, 5, and 1 mu l were dripped onto the surface of the ribbon and frequency shifts of about 220, 100, and 15 Hz, respectively, were obtained. The minimum number of MNPs was measured to be about 1.1x10(9), which corresponds to 0.025 mg or 1 mu l of MNPs.Öğe Magnetoimpedance effect of current-annealed CoNiFe/Cu microtubes(Elsevier, 2008) Atalay, F. E.; Kaya, H.; Atalay, S.A cobalt/nickel/iron (CoNiFe) magnetic layer was electrodeposited on a 50-mu m-diameter non-magnetic Cu wire in a sulphate bath using a constant voltage. Electrodeposited CoNiFe composite wires were submitted to current annealing at 540 mA. It was found that annealing time less than 1 min removes internal stresses produced during fabrication and that annealing times longer than 5 min induce circumferential anisotropy. Non-annealed sample showed a magnetoimpedance (MI) ratio of 412%. A maximum MI ratio of 583% was obtained after I min of current annealing. (C) 2008 Elsevier B.V. All rights reserved.
