Yazarlar

• Erdem, O.(2)
• Demir, I.(1)
• Duz, I.(1)
• Gencer, A.(1)
• Guner, S. B.(1)
• Hossain, S.(1)
• Kapucu, V.(1)
• Ozturk, K.(1)
• Yanmaz, E.(1)
• Çelik, S.(1)

• MakaleYalnız künye2019Scopus SJRQ2/r/bayburt/13303
  Comparative study of hot and cold press and their effect on superconducting properties of coronene added bulk MgB2

  Erdem, O.

  In this study, the superconducting properties of 4 wt% coronene (C24H12) added polycrystalline bulk MgB2 samples prepared by hot pressing and cold pressing, were reported in detail. The results were compared to determine one of which pressing methods is more useful to substitute of carbon released from C24H12 into MgB2 structure and to increase the superconducting properties of MgB2. The lattice strain, crystallite size, residual resistivity, superconducting transition temperature (Tc), critical current density (Jc), flux pinning force density (Fp) and vertical/lateral levitation force (Fz, Fx) were analysed for the hot and cold pressed samples. The a-lattice parameter and Tc value reduced sharply for 4 wt% C24H12 added cold pressed sample, resulting in a notable decrease of increment ratio of Jc and Fp values, while the depressing of Tc is lower for 4 wt% C24H12 added hot pressed sample. The cold pressing strongly increased the lattice strain, confirming more C substitution, while the hot pressing ensured smaller crystallite size. The Jc and Fp values were respectively found as 4.6 × 103 A/cm2, 1.3 × 104 A/cm2, 5.8 × 103 A/cm2 and 1.8 × 108 N/m3, 5.1 × 108 N/m3, 2.3 × 108 N/m3 for the pure sample and, 4 wt% C24H12 added hot and cold pressed samples at 20 K, 4 T. The maximum repulsive and attractive levitation force values at 20 K in ZFC and FC regimes were obtained for the 4 wt% C24H12 added hot pressed sample. Finally, the hot pressing provides an effective way to substitute C into MgB2 lattice without a remarkable decrease of Tc value, ensuring more homogenous and compacted structure, more electron–phonon interaction and strong flux pinning force.

  AtıfScopus6·WoS6·OpenAlex6

  İncele
• MakaleAçık Erişim2014Scopus SJRQ3/r/bayburt/10800
  Comparison of Levitation Forces of Bulk MgB2 Superconductors Produced by Nano Boron and Carbon-Doped Nano Boron

  Duz, I.; Guner, S. B.; Erdem, O.; Demir, I.; Kapucu, V.; Çelik, S.; Ozturk, K.; Hossain, S.; Gencer, A.; Yanmaz, E.

  MgB2 bulk superconductors were prepared by hot press plus furnace heating method. Two types of boron powders were used, one is amorphous nano boron and the other is C-doped boron. Characteristics of superconductors were determined by XRD and resistance measurements. Systematic levitation force measurements were performed by using a modular system at low temperatures. These bulk superconductors showed around 9 N repulsive and 4 N attractive forces in the z-axis at 20 K at closest point to the cryostat lid which contains the MgB2 superconductor. These values slightly decreased by increasing temperature to 24 and 28 K for both samples. Comparing two samples, nano boron MgB2 showed slightly higher levitation force than C-doped MgB2 although C-doped MgB2 has higher attractive force value at the closest point. This situation points out that C-doped MgB2 is much proper for attractive force applications (as guidance force) while the nanoboron MgB2 sample is much appropriate for repulsive force (as levitation).

  AtıfScopus13·WoS13·OpenAlex17

  İncele