Magnetization and Critical Current of Yb1Ba2Cu3O7-x Samples Prepared by the Plasma-ark Melting and Rapid Quenching Method
The dependence of magnetization (σ) and critical current density (Jc) on annealing temperature was investigated for Yb1Ba2Cu3O7-x superconductor prepared by the plasma-arc melting and rapid quenching method (PMQ-method). It was found that σ and the superconducting volume fraction increased with annealing temperatures up to 980 °C and reached maximum values of 1.98 emu/g and 90% respective-ly, where particle size also increased to over 25 μm. Futhermore at annealing temperature of more than 980°C, drastic changes in the magnetization curves and an increase in Jc were observed. From X-ray diffraction analysis and EPMA observation, it was found that small Yb2Ba1Cu1O5 particles (1mm diameter) segregated in the large Yb1Ba2Cu3O7-x grain (25 ym diameter). Using the high density and large grain of Yb1Ba2Cu3O7-x ceramics prepared by the PMQ method, grain-boundary Josephson junction effects were examined. Bridges with S-N-I-N-S weak links were fabricated with good reproducibility and showed microwave induced Shapiro steps at 77K.
KeywordsMagnetization Curve Critical Current Density Josephson Junction Magnetic Field Dependence Mechanical Procedure
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