Critical Current Density and Irreversibility Line of CuBa2Ca3Cu4Oy
The critical current density and irreversibility line of the single-phase polycrystalline sample of CuBa2Ca3Cu4Oy with Tc=l17 K have been estimated from measurements of magnetic hysteresis loops assuming Bean critical state model. Simple power law relations, Jc∝H-m, are observed in the magnetic field dependence of the intragrain Jc. Values of the intragrain Jc in a magnetic field of 1 T are about 106 and 104 A/cm2 at temperatures of 5 and 77 K, respectively. An exponential decay of the Jc with increasing temperature, Jc∝exp(-T/T0), is observed below 60 K. The characteristic temperature T0 of Cu-1234 is T0=16.1 K in a magnetic field of 1.0 T. The dependence of the Jc on temperature is relatively small among the oxide superconductors. Simple power law relations, Jc∝(l-T/Tc)n, are found in whole ranges of the temperature and magnetic field. The value of n is 5.24 for a magnetic field of 1.0 T The irreversibility fields at 70 and 77 K are estimated to be 9.5 and 3.7 T, respectively. The temperature dependence of the Hirr is fitted by Hirr=a(l-T/Tc)n with a=2130 and n=5.91.
KeywordsMagnetic Field Critical Current Density Magnetic Field Dependence Magnetic Hysteresis Loop Field Cool
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- 7.A. Iyo, K. Tokiwa, T. Kanehira, H. Ozawa, N. Kobayasi, N. Terada, M. Tokumoto, M. Hirabayasi and H. Ihara, Advances in Superconductivity VII (ISS94):825 (1994).Google Scholar
- 8.K. Tokiwa, T. Kanehira, K. Shiroki, H. Ozawa, Y.S. Song, A. Iyo, N. Terada, M. Tokumoto, M. Hirabayashi and H. Ihara, Advances in Superconductivity VII (ISS94):261 (1994).Google Scholar