Papers by Author: Hiroya Imao

Abstract: We prepared SmBa2Cu3Oy (SmBCO) superconducting bulks by partial melting growth with a top seed. From the results, we found that the SmBCO bulks prepared by melting process showed good superconductivity, where the critical temperature Tc and the temperature transition width ΔT of the bulk were 94K and about 1K, respectively. The as-prepared bulks required annealing at 500°C for 24h to improve the superconductivity. However, the characteristics of the bulks may be improved by more detailed study, for example optimum preparation and annealing conditions.

Abstract: We deposited Bi2Sr2Ca1Cu2Oy (Bi-2212) superconducting thin films on MgO substrates with or without Al2O3 particles by the rf magnetron sputtering method. From the results, we found that optimum target-substrate distance, rf powers and substrate temperature for obtaining the Bi-2212 films on the MgO substrates were 5mm, 150W and 830°C, respectively. The Bi-2212 films were Bi-2212 single-phase and had the Tc of about 54K . The particle size and the distribution density of Al2O3 were controlled by annealing temperature. The Bi-2212/Al2O3/MgO film showed Bi-2212 single-phase, whereas did not show zero-resistance.