Browsing by Author "Aktas, B"

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    Thickness dependence of magnetic properties of Co90Fe10 nanoscale thin films
    (AMER SCIENTIFIC PUBLISHERS) Yalcin, O; Kazan, S; Sahingöz, R; Yildiz, F; Yerli, Y; Aktas, B
    Ferromagnetic monolayers Co90Fe10 thin films with individual layer thicknesses 2, 6, and 8 nm were grown on thermally oxidized Si substrate and magnetic properties of these were investigated with Ferromagnetic resonance (FMR) technique at room temperature. The magneto resistance (MR) of the samples were measured as a function of applied DC magnetic field and the thickness dependence of the MR was plotted. The FMR spectra were recorded for both parallel and perpendicular geometry. The X-band (9.5 GHz) FMR spectra and resonance field of samples were analyzed and fitted theoretically by using the Landau-Lifshits dynamic equation of motion for magnetization with the Bloch-Bloembergen type damping term. The computer programs have been written to extract the effective magnetization (M), g-values and spin-spin relaxation time (T-2) fitting parameters. The thickness dependence of magnetic parameters has been obtained from experimental data by mean of a theoretical model.
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    English
    (0888-0018) Oztarhan, K; Guler, S; Aktas, B; Arslan, M; Salcioglu, Z; Aydogan, G
    TAYLOR & FRANCIS INC
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    Magnetic anisotropy studies on FeNiCo/Ta/FeNiCo three layers fllm by layer sensitive ferromagnetic resonance technique
    (WILEY-V C H VERLAG GMBH) Yildiz, F; Kazan, S; Aktas, B; Tarapov, S; Samofalov, V; Ravlik, A
    Two ferromagnetic layers that are separated by a non-magnetic spacer have been deposited in the presence of an external Dc magnetic field that has been applied in a mutually perpendicular direction during the deposition of each layer. This thin three-layer film of FeNiCo/Ta/FeNiCo was then studied by electron spin resonance (ESR) technique for different directions of the external magnetic field with respect to the film plane. Beside very anisotropic and strong two main modes, relatively well-resolved and very weak subsidiary peaks in ESR spectra were observed on low field side of the main modes for almost every direction of the external field. The anisotropic behavior as the field is rotated from the film normal towards to the film plane is due to strong demagnetizing field. However, two fold (axial) small anisotropies having 90 degrees phase shifts with respect to the peaks from two different layers were seen to originate from field-induced anisotropy. The small peaks are attributed to magnetostatics modes as well. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Ferromagnetic resonance studies on (Co40Fe40B20)x(SiO2)1-x granular magnetic films
    (ELSEVIER) Yildiz, F; Kazan, S; Aktas, B; Tarapov, SI; Tagirov, L; Granovsky, B
    Magnetic properties of granular (Co40Fe40B20)(x)(SiO2)(1-x) thin films (x = 0.37-0.53) have been studied by ferromagnetic resonance (FMR) technique. Samples have been prepared by ion-beam deposition of Co-Fe-B particles and SiO2 on sitall ceramic substrate. The FMR measurements have been done for different orientations of DC magnetic field with respect to the sample plane. It was found that the deduced value of effective magnetization from FMR data of the thin granular film is reduced by the volume-filling factor of the bulk saturation magnetization. The overall magnetization changes from 152 to 515 G depending on the ratio of the magnetic nanoparticles in the SiO2 matrix. From angular measurements an induced in-plane uniaxial anisotropy has been obtained due to the preparation of the film conditions as well. (c) 2005 Elsevier B.V. All rights reserved.