Yazar "Kolat, VS" seçeneğine göre listele

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    The effect of furnace annealing and surface crystallization on the anisotropy, ?E and magnetoimpedance effects in Fe71Cr7Si9B13 amorphous wires
    (Iop Publishing Ltd, 2004) Bayri, N; Kolat, VS; Atalay, FE; Atalay, S
    The dependence of the magnetization loops, coercivity, anisotropy constant, DeltaE and magnetoimpedance (MI) effects in positively magnetostrictive Fe71Cr7Si9B13 amorphous wires on annealing conditions were studied. Samples were annealed at temperatures of 440degreesC and 460degreesC for durations between 0.3 and 300 min. The results indicate that progressive annealing first leads to relief of internal stresses and annealing of wires at 460degreesC for 60 min produces the minimum coercivity of about 1 A m(-1). Further annealing increases the coercivity and anisotropy, due to partial crystallization at the surface. It was found that the anisotropy changes its direction to the circumferential direction with the surface crystallization. The maximum change in Young's modulus was measured to be about 75% in a partly surface crystalline sample. It was observed that the magnitude of the MI effect of the stress relieved sample could exceed 200% at 1 MHz.
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    Effect of hydrogen charging on the electrochemical and magnetic properties of Fe73.5M1Nb3Si13.5B9 (M = Cu, Pt, Pd, Ag, Mn) alloys
    (Wiley-V C H Verlag Gmbh, 2002) Kolat, VS; Turkdemir, H; Adigüzel, HI; Atalay, FE; Atalay, S; Sovak, P
    The effects of hydrogen absorption on the electrochemical, magnetic and magnetoelastic properties of amorphous Fe73.5M1Nb3Si13.5B9 alloys (M = Cu, Pt, Ag, Pd, Mn) were investigated. Hydrogen was charged cathodically for 30 min with cathodic current density of 50 A/m(2) in all samples using 0.5 M H2SO4 solution with 0.1 g/l As2O3 as a poison. It was observed that the partial substitution of Pt. Mn, Ag, Pd for Cu in Fe73.5Cu1Nb3Si13.5B9 has a great influence in the hydrogen absorption properties.
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    Hydrogen effect on the field dependence of Young's modulus of FeCuNbSiB alloy
    (Elsevier Science Sa, 2002) Kolat, VS; Bayri, N; Atalay, S
    The magnitude of the magnetic field dependence of Young's modulus of FeCuNbSiB alloys was found to decrease after hydrogenation but to nearly recover after 2-3 h. A large variation in the magnetic and the magnetoelastic properties of as-received sample was observed after hydrogenation. DeltaE and M-H results of samples annealed at 450degreesC showed that annealing could reduce hydrogen permeation into the sample. Practically no variation in the magnetic and magnetoelastic properties of samples annealed at 550degreesC were observed before and after hydrogenation. (C) 2002 Elsevier Science B.V. All rights reserved.
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    Magnetic and electrical properties of La0.67Ca0.33Mn0.9V0.1O3 two-phase composite
    (Elsevier, 2006) Kolat, VS; Gencer, H; Atalay, S
    In this work, we present magnetic and electrical properties of La0.67Ca0.33Mn1-xVxO3 (x=0 and 0.1). Polycrystalline La0.67Ca0.33MnO3 and La0.67Ca0.33Mn0.9V0.1O3 samples were prepared by conventional solid-state reaction. Two Curie temperatures for the La0.67Ca0.33Mn0.9V0.1O3 sample were observed at T-c1 = 223 K and T-c2 = 190 K. The undoped La0.67Ca0.33MnO3 sample showed only one magnetic transition temperature at 267K. The temperature dependence of resistance showed two maxima in the V-doped sample, and the peak value of magnetoresistance (MR) around the Curie temperature increased with V doping. Double maxima ill the resistance-temperature and magnetisation-temperature Curves are explained by the existence of two phases ill La0.67Ca0.33Mn0.9V0.1O3 samples. (c) 2005 Elsevier B.V. All rights reserved.
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    Magnetic entropy change in Fe74-xCrxCu1Nb3Si13B9 (x=14 and 17) amorphous alloys
    (Elsevier Science Bv, 2005) Atalay, S; Gencer, H; Kolat, VS
    In this study, the magnetic entropy variation in Fe74-xCrxCu1Nb3Si13B9 (x = 14 and 17) amorphous alloys was investigated. The temperature dependence of the magnetic entropy variation was calculated from the magnetization data. It was found that the Curie temperature of the sample decreases with increasing Cr content. The maximum entropy change corresponding to a magnetic field variation of 3 T is about 0.9 J/kg K for Fe60Cr14Cu1Nb3Si13B9 and 0.6 J/kg K for Fe57Cr17CU1Nb3Si13B9. (c) 2005 Elsevier B.V. All rights reserved.
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    Magnetocaloric behaviour in Fe57Cr17Cu1Nb3Si13B9 soft magnetic alloys
    (Wiley-V C H Verlag Gmbh, 2004) Kolat, VS; Atalay, S
    In this study, the magnetocaloric effect in as-received and nanocrystalline Fe57Cr17Cu1Nb3Si13B9 alloys in ribbon form was investigated The temperature dependence of the magnetic entropy variation, DeltaS(m), was calculated from the magnetisation data. It was found that the Curie temperature of the as-received amorphous sample is 156 K and the maximum entropy change occurs at this temperature. The calculated value of the maximum entropy change under 6 T magnetic field is about 1 J/kg.K in as-received amorphous ribbon and 1.12 J/kg.K for nanocrystalline sample under 5 T magnetic field.
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    Magnetocaloric effect in the La0.62Bi0.05Ca0.33MnO3 compound
    (Elsevier, 2005) Gencer, H; Atalay, S; Adiguzel, HI; Kolat, VS
    Bi-doped lanthanum manganite with chemical composition of La0.62Bi0.05Ca0.33MnO3 has been prepared by the standard solid-state process. The effect of Bi doping on the sintering temperature, the magnetic and magnetocaloric properties has been investigated. Bi2O3 was found to be an effective sintering aid for La0.67Ca0.33MnO3. It was found that small amounts of Bi doping (x = 0.05) can lower the sintering temperature about 200 degrees C. Bi-doped samples also exhibited a large magnetic entropy change, vertical bar Delta S-m vertical bar 3.5 J/kg K under 1 T field at the Curie temperature. (c) 2004 Elsevier B.V. All rights reserved.