Journal article
Direct evidence for negative grain boundary potential in Ca-doped and undoped YBa2Cu3O7-x
Using electron holography in a transmission electron microscope, we obtained direct evidence for the reduction of negative charge at grain boundary dislocations in Ca-doped YBa2Cu3O7 (YBCO) when compared to undoped YBCO. Because of the finite width of the valence band in the superconducting CuO2 planes, the negative grain boundary charge can lead to a depletion of electron holes available for superconductivity.
A significant reduction in the size of the perturbed region in the Ca-doped samples appears to be the principal mechanism for the improved interfacial superconductivity.
Language: | English |
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Year: | 2004 |
Pages: | 195502 |
ISSN: | 10797114 and 00319007 |
Types: | Journal article |
DOI: | 10.1103/PhysRevLett.92.195502 |