Abstract
High temperature, Tc>90 K, superconductivity in YBa2Cu3O7−δ samples was observed from resistivity and magnetic susceptibility measurements. The zero-field-cooled susceptibility of the material was 60 to 100% of the ideal diamagnetic value depending on sample preparation. Structure identification by X-ray diffraction at both 293 and 89 K exhibited the same orthorhombic structure. Scanning tunnelling microscope investigations of the sample surface revealed steep step structure with 10×10 nm² size crystallites and 5 to 100 nm high terraces. Temperature cycling between 77 and 293 K sometimes led to the appearance of white barium lumps on the surface and in the bulk of the sample causing the transition to the low resistance state at 90 K to disappear.
Original language | English |
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Pages (from-to) | 1203-1206 |
Journal | Journal of Materials Science |
Volume | 24 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1989 |
MoE publication type | A1 Journal article-refereed |