Changes in YBCO Single Grain Bulk Superconductor Exposed to Air Moisture
S. Piovarčia, V. Antala, M. Kaňuchováb, M. Radušovskáa, P. Dikoa
aInstitute of Experimental Physics SAS, Watsonova 47, 040 01 Košice, Slovakia
bFaculty of Mining, Ecology, Process Control and Geotechnology, Technical University of Košice, Park Komenskeho 17, 042 00 Košice, Slovakia
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Changes in bulk single grain YBCO superconductor at exposition to air were studied. The increase of the sample weight caused by reaction with air moisture was observed by weighing the samples over two months period. Thermal analyses and mass spectrometry of the exposed samples has shown evolution of water and oxygen during sample heating. Observation with scanning electron microscope confirmed the formation of some nanosize phases at the inner sample surfaces. XPS spectra done on the freshly cleaved and on the air exposed (001) surfaces confirmed changes in Ba and Cu bonds. Observed structural changes did not caused systematic changes in measured trapped field.

DOI: 10.12693/APhysPolA.126.364
PACS numbers: 74.72.-h, 74.25.-q, 68.43.-h, 68.37.-d