Browsing by Author "Arslan A."

Now showing 1 - 3 of 3

Experimental and theoretical approaches for magnetic, superconducting and structural characterization of Bi1.75Pb0.25Sr2Ca2Cu3-xSnxO10+y glass ceramics
(2017-12-01) Koralay H.; Cavdar S.; Arslan A.; Ozturk O.; Tasci A.T.; Tugluoglu N.
In this work, the effect of the partial substitution of Sn for Cu on structural, electrical and magnetic properties in the superconducting ceramic glass Bi1.75Pb0.25Sr2Ca2Cu3-xSnxO10+y system (x = 0, 0.1, 0.5) has been examined. The structural characterization of samples produced by glass-ceramic technique were done by X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements. The electrical and magnetic properties were determined by resistance-temperature (R-T) measurement and magnetization-magnetic field measurement (M-H) in the low temperature by using vibrating sample magnetometer (VSM), respectively. From the results of R-T measurement, the value of critical temperature (Tcoffset) has been decreased from 98 K to 73 K with increasing Sn- concentration. The critical current density has also been decreased with increasing magnetic field intensity. It has been observed from M-H plots that it was decreased with increasing the value of temperature. We have observed from M-H curves that the area size of the hysteresis curve decreases with increasing the value of temperature.
Structural and mechanical characterization of Bi1.75Pb 0.25Sr2Ca2Cu3-xSnxO 10+y superconductor ceramics using Vickers microhardness test
(2013-11-01) Koralay H.; Arslan A.; Cavdar S.; Ozturk O.; Asikuzun E.; Gunen A.; Tasci A.T.
In this work we investigated the role of Sn doping on mechanical and structural properties of Bi1.75Pb0.25Sr2Ca 2Cu3-xSnxO10+y (x = 0.0, 0.1, 0.3 and 0.5) superconducting ceramic material. All samples were fabricated with glass ceramic method. The prepared samples were characterized by using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray powder diffractometer (XRD) and static microhardness indenter. Surface morphology, orientation of grains, and elemental composition analysis of the samples were made by SEM and EDS measurements, respectively. Texturing and lattice parameters a and c were determined by XRD measurements. Load dependent and load independent microhardness, elastic modulus, yield strength and fracture toughness were obtained by hardness measurements. In this work we focused on Vickers microhardness measurements in order to characterize the mechanical properties of our samples. Experimental results of Vickers microhardness measurements were analyzed by using Meyer's law, the elastic/plastic deformation model, proportional sample resistance model (PSR), modified PSR model and Hays-Kendall (HK) approach. From these analyses, HK approach was determined as the most successful model describing the mechanical properties of our samples. Finally in this study, the changes on the mechanical and microstructural properties of Sn doped Bi-2223 superconductors and their possible reasons were also discussed in detail. © 2013 Springer Science+Business Media New York.
The effects of film thickness on the optical properties of TiO 2-SnO2 compound thin films
(2011-12-01) Sönmezolu S.; Arslan A.; Serin T.; Serin N.
In this work, TiO2-SnO2 compound thin films was synthesized by the sol-gel technique, and the effects of film thickness on the optical and structural properties of these thin films were investigated. Optical constants such as the refractive index, extinction coefficient, dielectric constant and third-order optical nonlinear susceptibility were determined from the measured transmittance spectra in the wavelength range 300-1500 nm using the envelope method. Meanwhile, the dispersion behavior of the refractive index was studied in terms of the single-oscillator Wemple-DiDomenico (W-D) model, and the physical parameters of the refractive index dispersion parameter and the dispersion energy were found. Furthermore, the optical band gap values were calculated by the W-D model and the Tauc model, respectively. It is observed that the values obtained from the W-D model are in quite good agreement with those determined from the Tauc model. Important changes in optical and dielectric constants were observed by means of variation in film thickness. To examine the structure of the thin films, x-ray diffraction (XRD) methods were used. Combined with XRD analysis, the observed variations in both the refractive index and optical band gap are directly correlated with the structural evolution of the composite TiO2-SnO2 thin films. The most significant results of the present study are that the thickness of the film can be used to modify the optical, structural and dielectric properties of TiO 2-SnO2 thin films. © 2011 The Royal Swedish Academy of Sciences.