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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 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 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 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 Nanowires of Lead-Free Solder Alloy SnCuAg(Hindawi Ltd, 2011) Atalay, F. E.; Avsar, D.; Kaya, H.; Yagmur, V.; Atalay, S.; Seckin, T.Ternary Sn88Ag5Cu7, Sn93Ag4Cu3, Sn58Ag18Cu24, Sn78Ag16Cu6, Sn90Ag4Cu6, Sn87Ag4Cu9 alloy nanowires were produced at various values of deposition potential by dc electrodeposition on highly ordered porous anodic alumina oxide (AAO) templates. During the deposition process some parameters, such as ion content, deposition time, pH, and temperature of the solution, were kept constant. The diameter and length of regular Sn93Ag4Cu3 nanowires electrodeposited at -1V were determined by scanning electron microscopy (SEM) to be approximately 200-250 nm and 7-8 mu m, respectively. Differential scanning calorimetry (DSC) results indicate that the melting onset temperature of Sn93Ag4Cu3 nanowires is about 204 degrees C.Öğe Production of Y-Ba-Cu-O Nanowires and Nanotubes by Electrochemical Method(Polish Acad Sciences Inst Physics, 2013) Kaya, H.; Atalay, F. E.; Avsar, D.; Yagmur, V.; Atalay, S.In this work, the technological aspects of great importance YBa2Cu3O7-x superconducting materials were produced in the form of nanotube by electrochemical method. The electrochemical deposition conditions for the Y-Ba-Cu deposition in nanoporous Al2O3 were investigated. The heat treatment was applied to Y-Ba-Cu/Al2O3 nanopatterns, to form superconductive phase. The resulting nanostructures were found to be in length 4-5 mu m, 177-210 nm in diameter. The produced nanostructures at -4 V and more positive potentials were Y-Ba-Cu nanowires, while the nanostructures deposited at the more negative potentials were of nanotube form. DOI: 10.12693/APhysPolA.123.209Öğe The synthesis of ferromagnetic La0.75Ca0.25MnO3 nanowires by a sol-gel method(Natl Inst Optoelectronics, 2010) Atalay, F. E.; Yagmur, V.; Atalay, S.; Kaya, H.; Tari, S.; Avsar, D.In this study, densely packed La0.75Ca0.25MnO3 (LCMO) nanowires were synthesized within a porous anodic aluminum oxide (AAO) template by means of a sol-gel method using nitrate as raw material and ethylene glycol as the chelating agent. It was observed from measurements of hysteresis curves that the magnetic behavior of the LCMO nanowire arrays was strongly dependent on the pH of the solution. As it has been reported that bulk polycrystalline La0.75Ca0.25MnO3 samples have a Curie temperature of 224 K [1], it is interesting to find that nanowires produced at pH 3 show ferromagnetic properties at room temperatureÖğe Torsion sensor based on the coil-less fluxgate effect(Elsevier Science Sa, 2012) Atalay, S.; Bayri, N.; Fidan, A.; Atalay, F. E.; Yagmur, V.The torsion dependence of the coil-less fluxgate properties of amorphous (Co-0.94 Fe-0.06)(72.5)Si-12.5 B-15 wire was investigated. The results show that the second harmonic of the output voltage from the wire ends, U-wire, varied linearly at the +/- 30 pi rad/m torsion range for as-cast wire and +/- 5 pi rad/m torsion range for annealed wire. It was also found that if the sample was annealed at higher torsion, the curve shifted negatively or positively depending on the direction of torsion applied during the annealing. Most importantly, the output signal changed its sign as the direction of external torsion reversed, and therefore the proposed torsion sensor could detect whether torsion was in the negative or positive (clockwise or anti-clockwise) direction. (C) 2012 Elsevier B.V. All rights reserved.
