[en] The Bi-Sr-Ca-Cu-O superconductor with the nominal composition (1113) were prepared. An orthorhombic unit cell (a=0.544nm, b=0.543nm, c=3.07nm) was determined by X-ray diffraction. The resistance transition curve shows that the sample has an onset around 110Κ and the zero resistance temperature at 85Κ. The mutual inductance measurement also shows a two-step transition which correspond to two superconducting phases as well as that in the resistive transition. The specific heat measurement was performed in the range of 56Κ to 130Κ by continuous scanning method. A simple extrapolation of the curve was made both from below and above T_c to yield ΔC=45mj/g.Κ and ΔC/T_c=0.49mj/g.Κ². From these values, the Sommerfeld constant γ and the Debye temperature θ_D were estimated

[en] From the NMR measurements, the authors compare the spin fluctuations spectrum in high-T_c cuprates and the pressure-induced paramagnetic state of YMn₂. It is pointed out that the latter has a shorter magnetic correlation length and the bandwidth is smaller by one order in magnitude than the former

[en] In this paper the authors reports on the preparation of the superconducting Bi-Sr-Ca-Cu-O thin films on SrTiO₃ (100) substrates by a Nd:YAG laser, which provides laser pulses with wavelengths of 1.06μm and pulse width of 200 ns. After the heat treatment at 850 degrees C for half an hour in oxygen flow, the samples exhibit superconductivity with the zero resistance at 66.8K and the onset temperature around 84K. X-ray diffraction analyses show that the samples have the preferred orientation with the c-axis perpendicular to the substrate

[en] The Bi-Sr-Ca-Cu-O superconductors with the nominal composition (1113) were prepared. An orthorhombic unit cell (a=0.544nm, b=0.543nm, c-3.07nm) was determined by X-ray diffraction. The resistance transition curve shows that the sample has an onset around 110 K and the zero resistance temperature at 85 K. The mutual inductance measurement also shows a two-step transition which correspond to two superconducting phases as well as that in the resistive transition. The specific heat measurement was performed in the range of 56 K to 130 K by the continuous scanning method. A simple extrapolation of the curve was made from below and from above T_c to yield ΔC=45 mJ/g.K and ΔC/T_c = 0.49 mJ/g.K.² From these values, the Sommerfield constant γ and the Debye temperature θ_D were estimate

[en] The preliminary study on the electron spin resonance (ESR) for the Bi_2-chiPb_chiSr₂Ca₂Cu₃O_y system has been made at room temperature. It is found that no significant ESR signal appears for Pb-substituted BiPbSrCaCuO system with RT, but a strong ESR signal was found for BiSrCaCuO system with 90Κ superconducting transition under the same experimental conditions. These might be attributed to the Cu³⁺/Cu²⁺ ratio in the bismuth based systems. A possible role of Pb in the Bi_2-chiPb_chiSr₂Ca₂Cu₃O_y system is discussed