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Article Citation - WoS: 11Citation - Scopus: 11Microstructural, thermal, and electrical properties of Bi1.7V0.3Sr2Ca2Ca3Ox glass-ceramic superconductor(Wiley-v C H verlag Gmbh, 2004) Kayed, TS; Calinli, N; Aksu, E; Koralay, H; Günen, A; Ercan, I; Cavdar, SA glass-ceramic Bi1.7V0.3Sr2Ca2Cu3Ox superconductor was prepared by the melt-quenching method. The compound was characterized by scanning electron microscopy, x-ray diffraction, differential thermal analysis, current-voltage characteristics, transport resistance measurements, and Hall effect measurements. Two main phases (BSCCO 2212 and 2223) were observed in the x-ray data and the values of the lattice parameters quite agree with the known values for 2212 and 2223 phases. The glass transition temperature was found to be 426 degreesC while the activation energy for crystallization of glass has been found to be E-a = 370.5 kJ / mol. This result indicates that the substitution of vanadium increased the activation energy for the BSCCO system. An offset T-c of 80 K was measured and the onset T-c was 100 K. The Hall resistivity rho(H) was found to be almost field-independent at the normal state. A negative Hall coefficient was observed and no sign reversal of rho(H) or RH could be noticed. The mobility and carrier density at different temperatures in the range 140-300 K under different applied magnetic fields up to 1.4 T were also measured and the results are discussed.Article Citation - WoS: 3Citation - Scopus: 3Effect of Magnetic Field and Γ Irradiation on the Properties of Tl-2212 Superconducting Tape(Wiley-v C H verlag Gmbh, 2002) Kayed, TS; Ercan, IThe critical temperature and critical current of Tl-2212 superconducting sample in the form of a tape have been studied near T-c under magnetic field and gamma irradiation. T-c decreases from 109 to 94 K with increase of magnetic field up to 300 mT. In 77-109 K range, J(c) decreases rapidly in low fields up to around 50 mT followed by a very slow decrease in J(c) up to 300 mT. T-c of the sample did not change up to 100 MR gamma dose and then started to decrease from 109 to 102 K with increase of gamma dose up to 800 MR, most of the change taking place in high doses. The critical currents of the sample decreased steadily with gamma irradiation up to 600 MR after which no further change was noticed.Article Citation - WoS: 2Citation - Scopus: 2Voltage-Current Characteristics of Bi-2223 Superconducting Tape Near Tc Under Γ Irradiation(Wiley-v C H verlag Gmbh, 2004) Kayed, TS; Ercan, IVoltage-current characteristics at four different applied magnetic fields (7, 20, 30, and 40 mT) of Bi2Sr2Ca2CU3Ox superconducting tape were measured in the temperature range from 100 to 115 K. They were also measured at zero magnetic field before and after gamma irradiations up to 10 MRad at different temperatures just below the critical temperature. The data were fitted to a power law expression V = I (beta(T)) in which the exponential parameter P under 20 mT field and after irradiation is found to fluctuate around three and then drops to unity near the critical temperature which may be interpreted as a sign of Kosterlitz-Thouless transition. The electrical properties of the tape were found to be very sensitive to gamma irradiation where most of the changes take place in low gamma doses.
