Yazarlar

  • MakaleYalnız künye2016
    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.

  • MakaleYalnız künye2015
    Magnetic Relaxation in a Y 0.5Lu0.5Ba2Cu3O y Superconductor at Various Magnetization Levels

    Çelebi, S.; Ozturk, A.; Uysal, E.; Kutuk, S.; Duzgun, I.

    The evolution of the rate of flux creep along the major hysteresis envelopes in a Y0.5Lu0.5Ba2Ca3Oy sample synthesized by a modified melt powder melt growth (MPMG) method at 25 K has been investigated. Magnetic relaxation rates depend strongly on the prior magnetic history. Calculations based on the critical state model can reproduce quite well the experimental data for magnetization when we have chosen the field exponent n = 0.3 in critical current density, Jc(Ha) = Jc0/(Ha−IM)n, where IM = Ha when 0 < H < Hc1 and (Formula presented.) when Ha ≥ Hc1. Using the field-cooled magnetization MFC data as well as the comparison of experimental and calculated M–H hysteresis loop, we estimated Hc1 = 500 Oe, p = 0, and the penetration field H∗ = 20 kOe. The apparent pinning energy was estimated as 62 meV for the remanent magnetization upon an excursion of 40 kOe.