Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Conference Object Citation - WoS: 3Citation - Scopus: 3Low-Field Behavior of Ti-Added Mgb2/Cu Superconducting Wires(Institute of Electrical and Electronics Engineers Inc., 2005) Gençer, Ali; Kılıç, Ahmet; Okur, Salih; Güçlü, Nusret; Özyüzer, Lütfi; Belenli, İbrahimWe report on low-field magnetic properties of Ti-added (0-20 wt.% of Ti) Cu-clad MgB2 superconducting wires. Wires were produced by mixing appropriate amount of Ti and reacted MgB2 powder which was then placed inside Cu tubes with a diameter of 6 mm. The tubes were then cold worked by rolling or drawing to smaller diameters and then annealed at various temperatures to enhance the grain connectivity. XRD studies show that Ti addition results in new but minor phases. We have then measured ac susceptibilities in the temperature range between 20 K and 40 K in ac fields of 20-1600 A/m. The data show that an additional loss mechanism is established with Ti-addition. The calculated ac losses are increasing with increasing Ti-content in the main superconducting matrix.Article Citation - WoS: 4Citation - Scopus: 4Simultaneous Quasiparticle and Josephson Tunneling in Bscco-2212 Break Junctions(Institute of Electrical and Electronics Engineers Inc., 1999) Özyüzer, Lütfi; Miyakawa, Nobuaki; Zasadzinski, John F.; Yusof, Zikri M.; Romano, Pierom; Kendziora, Christopher A.; Hinks, David G.; Gray, Kenneth E.Tunneling measurements are reported for superconductor-insulator-superconductor (SIS) break junctions on underdoped, optimally-doped, and overdoped single crystals of tSrsCaCiOs-).,! (Bi2212). The junction I -V characteristics exhibit welldefined quasiparticle current jumps at eV = 2A as well as hysteretic Josephson currents. The quasiparticle branch has been analyzed in the framework of dxa_y2 (d-wave) superconductivity and indicates that there is preferential tunneling along the lobe directions of the d-wave gap. For overdoped Bi-2212 with TC-62 K, the Josephson current is measured as a function of junction resistance, Rn, which varied by two orders of magnitude (1 kO to 100 kO). IcRn product is proportional to the 0.47 power of /c and displays a maximum of 7.0 mV. When the hole doping is decreased from overdoped (Tc=62 K) to the underdoped regime (Tc=70 K), the average IcRn product increases as does the quasiparticle gap. The maximum IcRn is ~ 40% of the A/e at each doping level, with a value as high as 25 mV in underdoped Bi-2212.