Synthesis of YNi2B2C thin films by magnetron sputtering

Thin films of YNi2B2C superconductor by the magnetron sputtering technique have been synthesized. The YNi2B2C phase was found to crystallize very uniformly after annealing at 1050 °C in vacuum. The structure was investigated and the electric and magnetic properties were characterized. The films were c-axis oriented and showed a Tc onset of ~15 K by both magnetization and resistivity measurements. The results of the critical current measurement suggested the existence of anisotropies of pinning force and an upper critical field Bc2

Fabrication of Bi_2Sr_2CaCu_2O_8 Tapes and Coils(High-T_c Superconducting Materials Research)

Textured Bi_2Sr_2CaCu_2O_8/Ag composite tapes were fabricated by both doctor blade process and dip-coating process applying partial melting and subsequent slow cooling. Texturing significantly improved current transfer across the grain boundaries and increased transport J_c. At 4.2K, J_c values well above 10^5A/cm^2 were obtained up to 25T for the doctor blade processed tapes. Small coils with 50-70 turns were fabricated using the tapes prepared by the continuous dip-coating process. 0.6T and 0.36T were generated by the coils in bias field of 12T and 25T at 4.2K, respectively

Transport Characteristics of a Bi-2223 Solenoid Coil in High Magnetic Fields

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Applicability of Weibull Distribution to Description of Distributed Normalized Critical Current of Bent-Damaged Bi2223 Composite Tape

Critical current of bent-damaged Bi2223 composite tape differs from specimen to specimen. To describe the distributed critical current values of specimens, the three-parameter Weibull distribution function has been employed and has been demonstrated to describe the experimental results. In the present work, the reason for this was discussed by modeling analysis of the experimental results in a round robin test of VAMAS/TWA16. The distribution of the measured normalized critical current values was described well by using the damage evolution approach, in which the difference in damage evolution among the specimens was correlated to the distribution of critical current values. From this approach, the three-parameter Weibull distribution function for critical current values was derived, which gave almost the same parameter values for the minimum critical current, scale parameter and shape parameter as those obtained by the direct application of the Weibull distribution function to the experimental results. Based on this result, the reason why the normalized critical current values of bent-damaged composite tape is described by the three-parameter Weibull distribution function was accounted for in a quantitative manner by the difference in damage evolution among the specimens

The effect of oxygen partial pressure during heat treatment on the microstructure of dip-coated Bi-2212/Ag and Ag alloy tapes

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