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High-temperature superconductivity. Final report

Technical Report ·
OSTI ID:7248996
After the initial discovery of superconductivity over 30K in the La/sub 2/-XBaXCuO/sub 4/ system several groups confirmed the result both resistively and magnetically (flux expulsion). Ultimately, transitions were observed in the analagous compounds with Ba replaced with Ca7 and Sr7,8 for 0.1 less than or equal to x less than or equal to 0.3 with the highest Tc's above 40K. The author's samples were prepared from reagent-grade powders of La/sub 2/O/sub 3/, BaCO/sub 3/, SrCO/sub 3/, CaCO/sub 3/, PbO/sub 2/, and CuO. The powders were mixed in inappropriate ratios and calcined in air between 1000 and 1100C for 12 hours. The resulting materials were reground, pressed into small disks (nominally 1 cm diameter by 2 mm height) and sintered in air at 1000-1100C for 12h. The calcined powders and sintered pellets were x-rayed following each process to ensure that the proper phase was present.
Research Organization:
Naval Research Lab., Washington, DC (USA)
OSTI ID:
7248996
Report Number(s):
AD-A-190259/2/XAB
Country of Publication:
United States
Language:
English