Observations and model of a new ac-loss valley in a YBCO superconductor


Ozturk A. , Celebi S. , LeBlanc M.

SUPERCONDUCTOR SCIENCE & TECHNOLOGY, cilt.18, ss.1029-1034, 2005 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 18 Konu: 8
  • Basım Tarihi: 2005
  • Doi Numarası: 10.1088/0953-2048/18/8/001
  • Dergi Adı: SUPERCONDUCTOR SCIENCE & TECHNOLOGY
  • Sayfa Sayıları: ss.1029-1034

Özet

We report on measurements of the ac susceptibility of sintered YBCO pellets, with ZnO added, as a function of temperature T, for several different ac magnetic field amplitudes, Hac, in the presence of static bias magnetic field H-b directed along H-ac. For each choice of H-ac, the imaginary part of the ac susceptibility versus T traces a peak, denoted chi''(max), centred at a temperature denoted Tma, We find that chi"(max) versus both H-ac and T-max traces a valley. Calculations of hysteresis losses, exploiting the critical state model where the critical current density j(c) = alpha (T)/B-n, reproduce the experimental data quite well.