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    Crystallographic effects of Boron doping into Sm-Ca-Cu-O Ceramic
    (Elsevier, 2021) Guler, Munir Taner; Karaca, Ibrahim; Unluer, Sahin
    In this work, we have especially focused on investigating the nano Boron doping effect into the SmCa-Cu-O Ceramic [1,2 ]. The samples produced suitable with nominal composition selected as Sm1.75Ca(2.20-x)BxCu3.4Oy (x = 0.0; 0.4, 0.8 and 1.0). This effect investigated through the TG/DTA, XRD, and SEM results. Lattice parameters (a, b , and c) got from the crystallographic knowledge, and they carefully calculated. The crystallographic growth seen because of the changing at the intensity of x-ray diffraction peaks. Increasing the Boron doping in the matrix have produced the crystal growth at especially SmBP and SmB10 samples, peaks intensity at 29 degrees (220) Miller indices, has increased from 1.602 to 10.883, respectively. Namely, with increasing B-doping resulted in a transformation of the phase. In this way (at Boron free sample) it has achieved the orthorhombic phase transformation to the tetragonal phase created in the matrix. (C) 2021 Elsevier B.V. All rights reserved.
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    Origin of the exchange bias training effects in magnetically coupled soft/hard synthetic bilayers at low temperature
    (ELSEVIER SCIENCE BV, 2015) Yalcin, Orhan; Unluer, Sahin; Kazan, Sinan; Sahingoz, Recep
    Hysteresis loops of the nanoscale magnetic layer Co90Fe10 and Ni81Fe19 and bilayer Co90Fe10/Ni81Fe19 and Ni81Fe19/Co90Fe10 films were measured as a function of external dc magnetic Field and the thickness dependence of these Films were plotted as a function of temperature. Time evolution of the minor/middle/major hysteresis loops of 5/5 nm-thick Ni81Fe19/Co90Fe10 monolayer have been observed at 10 K. The spin valve, exchange bias training and Barkhausen effects for magnetic layer and bilayer films have been analysed at various temperatures, thicknesses and different orientations according to the substrate. The exchange-bias training effects have been observed only in positive magnetization region. Origin of the exchange-bias training effects and asymmetric hysteresis loops are related to the relaxation mechanism of a pinning layer in magnetically coupled soft/hard bilayers. (C) 2014 Elsevier B.V. All rights reserved
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    Refinement of the Low-Temperature Phase with Nano SnO Doping in Ba-Ca-Cu-O Ceramics
    (Elsevier, 2021) Unluer, Sahin; Karaca, Ibrahim; Simsek, Nihat
    The SnO nano dopant effects on to the low-temperature phase have studied by the selected composition of Ba2Ca3Cu6-xSnxOy (x = 0.0; 0.5; 1.0; 1.5; 2.0). The samples produced by Melt-Growth Method (MGM). As well-known, the BaCaCuO superconductor has two phases; one of them occurs in the high superconducting transition temperature at 126 K, but this phase is unstable and requires high pressure. Because of these unfavorable conditions, Ba-Ca-Cu-O superconductors out of practically be an application to technology. The other is the low-temperature phase, in which superconducting transition temperature is nearly at 90-95 K. In this work, we focused on investigating the low transition temperature phase. The phase has a Tetragonal crystal structure with a P4 / mmm symmetry and lattice constants a = 6.517 angstrom and c = 8.410 angstrom. The effects investigated by the differential scanning calorimetry, energy dispersive X-ray, scanning electron microscope, and X-ray powder diffraction method results. Structural analysis has shown that the matrix has infiltrated by the use of the SnO as a dopant. Namely, the SnO doping has resulted as the low-temperature phase has a growing percentage of 73.875% within the volume fraction of the matrix. (C) 2020 Elsevier B.V. All rights reserved.