İlgi alanları

• MakaleAçık Erişim2026/r/gumushane/19406
  NdBCO/YBCO/MgO ince film çekirdek kullanılarak TSMG yöntemiyle üretilen eklenmiş halka tipi YBCO külçe süperiletkeni

  Çakır, Bakiye; Basoglu, Mehmet; Aydıner, Alev; Duman, Şeyda; Batur, Kübra Nur

  Bu çalışmada NdBCO/YBCO/MgO (300 nm NdBCO/ 20 nm YBCO/ MgO) ince film çekirdeği ile üstten aşılama-eritme-büyütme [Top-Seeded-Melt-Growth (TSMG)] yöntemi uygulanılarak 32 mm çapında Y123 + %25 Y211 (YBCO) örnekleri ile Y123 + %25 Y211 + %20 Ag2O (YBCO-Ag2O) ekleme örneği üretildi. Üretilen üç adet YBCO örneği, YBCO-Ag2O ekleme örnekleri ile c-ekseni yönünde üst üste istiflenerek eklendi. Eklenmiş örnek su jeti kullanılarak süperiletken halka haline getirildi. Manyetik özelliklerini gözlemlemek için örneğin farklı bölgelerinden alınan kesitlerin manyetizasyon ölçümleri yapılarak kritik akım yoğunluğu değerleri hesaplandı. Yapısal özelliklerini gözlemlemek için X-ışını analizi ve polarize optik mikroskop görüntüleri alındı. Büyütme işlemi için kullanılan NdBCO/YBCO/MgO ince film çekirdekleriyle başarılı tek kristal örnekler üretildi. Elde edilen halka tipi örnekte, ek bölgelerden kesit alınan örneklerin, ana örneklere kıyasla daha kararlı bir manyetizasyon davranışı sergilediği görüldü.

  İncele
• MakaleAçık Erişim2025/r/gumushane/14311
  Superconducting Properties of Welded Three Top-Seeded YBa2Cu3O7−x Produced with NdBCO/YBCO/MgO Thin-Film Seed

  Batur, Kübra Nur; Duman, Şeyda; Çakir, Bakiye; Başoğlu, Mehmet; Aydiner, Alev

  This study investigates hollow single-crystal top-seeded melt growth (TSMG) YBa2Cu3O7−x (YBCO or Y123) samples welded with Ag-added TSMG YBCO solder materials produced using NdBCO/YBCO/MgO thin-film seeds. Three main samples and one solder material are produced by the TSMG method. In order to increase the dimensions of the bulk YBCO superconductor, two slices of the solder material and the main samples are stacked on top of each other with the c-axis parallel and welded at 1030 °C. X-ray diffraction patterns, polarized optical photographs, and SEM micrographs are taken to determine the structural properties of the samples. A preferential orientation in the c-axis is observed with a good connection. Low-temperature resistance and magnetization measurements are made for the specimens taken from the welding region. A sharp superconducting transition occurs at 0 T around 93 K for welding regions of W-ab and W-bc specimens. The critical current densities (Jc) are high as in the main samples. At the same time, the Jc values at 77 K and 0 T are found as 1.54 × 104, 1.98 × 104, 2.21 × 104, 2.31 × 104, and 2.36 × 104A cm−2 for the W-a, W-ab, W-b, W-bc, and W-c specimens, respectively. The single-grain feature is not impaired; thus, the absence of additional grain boundaries facilitates the current passage.

  İncele
• MakaleYalnız künye2025/r/gumushane/11700
  Impact of erbium doping on critical current density and constituent phase in BSCCO superconductors

  Açikel, S.; Cumhur, I.; Öztürk, A.; Başoğlu, M.; Düzgün, I.

  This work systematically examines the influence of partial substitution of calcium (Ca) by erbium (Er) on the structural integrity and superconducting performance of Bi2Sr2Ca2Cu3O10+δ (BSCCO) high-temperature superconductors. Samples were synthesized through the conventional solid-state reaction method and characterized via X-ray diffraction, scanning electron microscopy, resistivity, and magnetization measurements. Despite the close effective ionic radii of Er and Ca, experimental results revealed that increasing Er content led to a deterioration of the superconducting phase and the emergence of semicon ducting characteristics. Quantitative analyses demonstrated a notable reduction in critical current density (Jc), with undoped BSCCO samples exhibiting approximately 14% higher Jc values under equivalent conditions. These findings suggest that while ionic size considerations may permit Er substitution from a stoichiometric perspective, the structural and superconducting phase stability of the BSCCO matrix is adversely affected by Er incorporation.

  İncele
• MakaleYalnız künye2023/r/gumushane/14392
  The effect of the Y2O3 buffer layer on the microstructural and physical properties of melt-processed Y358 superconductor

  Başoğlu, Mehmet; Çakir, Bakiye; Duman, Şeyda; Aydiner, Alev

  The Y3Ba5Cu8O18 (Y358) superconductors were produced using the Melt-Powder-Melt-Growth (MPMG) method. In the crystal growth process, Y2O3 powder was used as a substrate in both powder and tablet form. The first sample was produced without using any buffer layer, the second sample was produced with a powdered Y2O3 buffer layer, and the third sample was produced with a tablet-form Y2O3 buffer layer. The effect of the Y2O3 substrate on the structural and physical properties of the Y358 superconductor samples was investigated. Superconducting phases were observed in all samples of Y358 through XRD measurements, confirming their presence. Samples fabricated using the powder and tablet forms of the Y2O3 substrate had a better microstructure than the sample fabricated without a Y2O3 substrate. The highest critical current density (J c) value was obtained at 77 K for the Y358 sample produced with a Y2O3 powder substrate, and the J c value was calculated as 1.2 × 104 A cm–2 according to the Bean model.

  İncele
• MakaleYalnız künye2023/r/gumushane/12586
  The effect of fabrication method on physical properties of different Y211 and 20% Ag2O added YBCO sample

  Duman, Şeyda; Çakır, Bakiye; Başoğlu, Mehmet; Küçükömeroğlu, Tayfur; Aydıner, Alev

  In this study, it is aimed to investigate the effects of production methods on the physical properties of 20% Ag2O and different ratios of Y211 added YBCO samples. In this context, the samples with Y123 + x % (x = 20, 25, 30) Y211 + 20%Ag2O compositions were fabricated by MPMG and TSMG methods in two groups to join YBCO main samples. XRD measurements were performed to determine the characteristic peaks. Trapped magnetic fields and vertical levitation forces between the bulk samples and a permanent magnet were measured using a computer-controlled system in ZFC at 77 K. From the XRD measurements, it was found that MPMG YBCO samples had a dominant superconducting structure and partially showed orientation peaks in the c-axis direction, while TSMG YBCO samples were single-crystal samples oriented along the c-axis. From the trapped magnetic field measurement results, the trapped magnetic field value of the Y123 + 25%Y211 + 20%Ag2O (TAg25) sample prepared by the TSMG method was higher than that of the other samples. Among the levitation force measurement results, the maximum repulsive force values of TAg25 and TAg30 (Y123 + 30%Y211 + 20%Ag2O) samples are the highest. At the same time, the hysteresis widths of these samples are also the highest, which proves that their flux-pinning potential is higher than that of the other samples.

  İncele
• MakaleYalnız künye2021/r/gumushane/14641
  The Effect of Grain Growth Temperature on the Trapped Magnetic Field of Y358 Superconductors

  Başoğlu, M.

  In this study, three different Y358 samples were produced by the melt-powder-melt-growth (MPMG) method at different maximum grain growth temperatures of 1030 °C, 1040 °C, and 1050 °C. The differential thermal analysis (DTA), X-ray powder diffraction (XRD), magnetic levitation force, trapped magnetic field values and magnetization measurements were performed. According to the results, the highest magnetic levitation force, the highest critical current density and the highest trapped magnetic field values were obtained from the sample produced at the temperature of 1050 °C.

  İncele
• MakaleYalnız künye2021/r/gumushane/12896
  Specification of Some Superconductivity Parameters by Adding Lutetium to the YBCO (358) Ceramic Superconductor

  Başoğlu, M.; Düzgün, I.; Öztürk, A.

  Superconducting specimens of Y3-xLuxBa5Cu8O18+δ (where x = 0, 0.2, 0.4, 0.5) ceramic were fabricated via the solid-state route (SSR). The structural and superconducting features of the specimens were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Measurements and calculations were carried out for electrical resistance (R-T) and DC magnetization (M-H). The onset critical transition temperature (Tconset) of the specimens dropped to lower temperatures with the addition of lutetium (Lu). The estimated critical current density (Jc) values of the specimens, depending on the magnetic field, were extracted from the DC magnetization data. The changes in average grain size and bulk critical current density were examined. Improvement was observed in the bulk critical current density with increasing levels of Lu/Y substitution.

  İncele
• MakaleYalnız künye2020/r/gumushane/14880
  Comparative Investigation on Magnetic Behavior of Partial Rare Earth Element (Re: Lu, Yb, and Dy) Substituted Y0.5Re0.5BCO (123) Superconductors

  Öztürk, Ali; Düzgün, İbrahim; Başoğlu, Mehmet; Çelebi, Selahattin

  Partial Re (rare earth elements: Lu, Yb and Dy) substituted YBaCuO (123) superconductors synthesized by solid-state reaction (SSR) procedure have been investigated via x-ray diffraction, scanning electron microscopy, a.c. magnetic susceptibility, and d.c. magnetization, and calculations. The measurements of a.c. magnetic susceptibility have been carried out at constant a.c. field amplitude and constant frequency for the samples studied. The temperature dependence of intergranular critical current density (Jcm) has been estimated from the a.c. magnetic susceptibility data. The d.c. magnetization measurements were performed at the temperatures of 5 K, 20 K, and 77 K separately. The variation of critical current density (Jc) with magnetic field (μ0H) has been evaluated from the d.c. magnetization data by using upper and lower branch of the major hysteresis curve. Lu substituted Y0.5Lu0.5BCO (123) sample shows higher critical current density than Yb and Dy substituted samples at low-temperature (lower than 77 K) regions.

  İncele
• MakaleAçık Erişim2017/r/gumushane/11360
  The effect of sintering in different atmospheres on superconductivity parameters of YBCO

  Başoǧlu, Mehmet

  YBa2Cu3O7 (Y123) is a superconductor material discovered in 1987 and its transition temperature is above the liquid nitrogen temperature. It is known that superconductor samples produced by the solid-state reaction route are very often sintered in air atmosphere. However, in the presented work, Y123 was prepared by the same technique using a sintering ambient composed of a mixture of oxygen and argon gases for the first time. Critical current densities of the samples were calculated using results of magnetization measurements. It was obtained from magnetization analysis that all the samples exhibited superconductor character. It was also observed that the sample sintered in the 50% oxygen and 50% argon atmosphere showed the highest critical current density.

  İncele
• MakaleYalnız künye2016/r/gumushane/14979
  Improvement of Current Density of Different Atmosphere-Sintered Y358 Superconductors

  Başoğlu, M.; Düzgün, İ.

  Y3Ba5Cu8O18 (Y358) which is the last family member of YBCO superconducting material was produced by a solid-state reaction technique. During the production process, superconducting samples were sintered in different atmosphere conditions. XRD measurements of the samples were performed. As a result of the measurements, it was seen that the superconducting phase peaks were formed. Hysteresis loops were calculated and analyzed in the framework of a critical state model including the Meissner current. Meissner currents (IM) were calculated as 0.0062, 0.0037, and 0.0119 for S100, S50, and S0, respectively. It was observed that S50 has the highest critical current density among the other calculated values.

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