The preparation and electrical properties of Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>y</sub> thick films with high T<sub>c</sub> on (100) MgO substrate
X L Wang; P L Steger; A Ritzer; B Hellebrand; S Proyer; E Stangl; X Z Wang; X L Wang; Johannes Kepler Univ., Linz, Austria; P L Steger; Johannes Kepler Univ., Linz, Austria; A Ritzer; Johannes Kepler Univ., Linz, Austria; B Hellebrand; Johannes Kepler Univ., Linz, Austria; S Proyer; Johannes Kepler Univ., Linz, Austria; E Stangl; Johannes Kepler Univ., Linz, Austria; X Z Wang; Johannes Kepler Univ., Linz, Austria
Журнал:
Superconductor Science and Technology
Дата:
1995-04-01
Аннотация:
Thick c-oriented films, of single-phase Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>y</sub> (Bi-2212) were prepared on (100) MgO substrates by employing a partial melting method. The effect of quenching on T<sub>c0</sub> was studied. The highest T<sub>c0</sub> obtained by resistance measurement was 92 K, whereas 93.2 K was achieved by AC susceptibility measurements. The best results for the critical current density J<sub>c</sub>, measured in zero magnetic field, were 1.3*10<sup>3</sup> A cm<sup>-2</sup> at 77 K and 7*10<sup>3</sup> A cm<sup>-2</sup> at 53 K. Near T<sub>c</sub> the temperature dependence of J<sub>c</sub> can be described by J<sub>c</sub> approximately (1-T/T<sub>c</sub>)<sup>2</sup>. At temperatures T<sub>c</sub><<T<sub>c</sub> the dependence of J<sub>c</sub> on temperature can be described by a homogeneous superconductor flux creep model.
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