Browsing by Author "Alper, Mursel"

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2D Magnetic texture analysis of Co-Cu films
(Walter de Gruyter Gmbh, 2017-05-01) Bayırlı, Mehmet; Karaağaç, Öznur; Koçkar, Hakan; Alper, Mursel; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; AAG-8795-2021; 7005719283
The magnetic textures for the produced magnetic materials are important concepts in accordance with technical applications. Therefore, the aim of this article is to determine 2D magnetic textures of electrodeposited Co-Cu films by the measurement of hysteresis loops at the incremented angles. For that, Co-Cu films were deposited with different Co2+ in the electrolyte. In addition, the easy-axis orientation in the films from the squareness values of the angles, M-p(beta) obtained by the hysteresis loops have been numerically studied using the Fourier series analysis. The differences observed in the magnetic easy-axis distributions were attributed to changes of the incorporation of Co2+ in the films with the change of Co2+ in the electrolyte. The coefficients of Fourier series (A(0) and A(2n)) were also computed for 2D films. It is seen that a systematic and small decrease in A(0) and an obvious decrease in A(2n) (n = 1) were observed with increasing incorporated Co in the films. Results imply that interactions cause slightly demagnetization effect accordance with higher incorporation of Co in the films. Furthermore, the crystal structure of the Co-Cu films analysed by X-ray diffraction revealed that the films have dominantly face-centred cubic structure. Film contents analysed by energy-dispersive X-ray spectroscopy and film morphologies observed by scanning electron microscope also support the magnetic texture analysis results found by numerical computation.
Electrical and optical properties of schottky diodes fabricated by electrodeposition of ni films on n-gaas
(Elsevier Science Sa, 2022-10-14) Haciismailoğlu, M. Cüneyt; Ahmetoğlu, Muhitdin; Haciismailoğlu, Murşide; Alper, Mursel; Batmaz, Tuğce; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Psikoloji Bölümü.; 0000-0002-0781-3376; 0000-0001-5648-3230; AAH-9719-2021; KDM-6805-2024; K-7950-2012
In this paper, we report electrical and optical characteristics of the Schottky diodes fabricated by electrodepo-sition of nickel onto n-GaAs substrate from 0.125 M NiSO4 + 0.25 M H3BO3 + 0.25 M Na2SO4 solution. The electrodeposition was performed at room temperature and at -1.5 V vs. SCE. Electrical and optical properties were measured in the temperature range of 200-360 K. Dark and light current-voltage (I-V) characteristics were investigated. Ideality factor, n and zero-bias barrier height, phi b were calculated and found to be almost constant in this temperature range. For room temperature, these values were obtained as 1.05 and 0.70 eV, respectively. Illuminated I-V characteristics were also investigated and they showed that the fabricated device could operate in photovoltaic regime. Open-circuit voltage, Voc was found to be 0.24 V for the diode under 20 mW/cm2 illumination.
Electrochemical, structural and magnetic analysis of electrodeposited CoCu/Cu multilayers: Influence of Cu layer deposition potential
(Springer, 2018-03) Koçkar, Hakan; Kuru, Hilal; Ünlü, Cumhur Gökhan; Tekgül, Atakan; Alper, Mursel; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0001-6737-3838; P-2124-2016; AAG-8795-2021; 37462175100; 7005719283
The electrochemical, structural and magnetic properties of CoCu/Cu multilayers electrodeposited at different cathode potentials were investigated from a single bath. The Cu layer deposition potentials were selected as , and with respect to saturated calomel electrode (SCE) while the Co layer deposition potential was constant at versus SCE. For the electrochemical analysis, the current-time transients were obtained. The amount of noble non-magnetic (Cu) metal materials decreased with the increase of deposition potentials due to anomalous codeposition. Further, current-time transient curves for the Co layer deposition and capacitance were calculated. In the structural analysis, the multilayers were found to be polycrystalline with both Co and Cu layers adopting the face-centered cubic structure. The (111) peak shifts towards higher angle with the increase of the deposition potentials. Also, the lattice parameters of the multilayers decrease from 0.3669 nm to 0.3610 nm with the increase of the deposition potentials from to , which corresponds to the bulk values of Cu and Co, respectively. The electrochemical and structural results demonstrate that the amount of Co atoms increased and the Cu atoms decreased in the layers with the increase of deposition potentials due to anomalous codeposition. For magnetic measurements, the saturation magnetizations, obtained from the magnetic curves of the multilayers were obtained as 212 kA/m, 276 kA/m, and 366 kA/m with , , and versus SCE, respectively. It is seen that the values increased with the increase of the deposition potentials confirming the increase of the Co atoms and decrease of the Cu amount. The results of electrochemical and structural analysis show that the deposition potentials of non-magnetic layers plays important role on the amount of magnetic and non-magnetic materials in the layers and thus on the magnetic properties of the multilayers.
Electrodeposited NiFeCu/Cu multilayers: Effect of Fe ion concentration on properties
(Elsevier, 2015-03-01) Kuru, Hilal; Koçkar, Hakan; Alper, Mursel; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0001-8220-6851; AAG-8795-2021; 7005719283
A series of 125[NiFeCu(3 nm)/Cu(1 nm)] multilayers were electrodeposited on strong (110) textured Cu substrates from electrolytes containing different Fe ion concentrations under potentiostatic control. The compositional analysis by energy dispersive X-ray spectroscopy demonstrated that as the Fe ion concentration in the electrolyte is increased, the Fe content of the multilayers increased. X-ray diffraction measurements indicated that all samples exhibited a face-centred cubic structure with a strong (110) texture as their substrates. The surface images obtained by scanning electron microscopy disclosed that all films have smooth surfaces. Magnetoresistance measurements were carried out at room temperature with magnetic fields up to +/- 12 kOe. All samples exhibited giant magnetoresistance (GMR) and the maximum GMR value of 5% was obtained in the multilayer grown from the electrolyte containing 0.0036 M Fe ion concentration. The GMR magnitude changed depending on the film contents arising from the variation of the Fe ion concentration in the electrolyte. The magnetic properties studied with the vibrating sample magnetometer showed that the saturation magnetisation changed, and the coercivities decreased with varying Fe ion concentration in the electrolyte. The changes observed in the properties were ascribed to the variations observed in the film composition caused by the Fe ion concentration of the electrolyte.