ISSN:
1573-2746
Keywords:
grain boundaries
;
misfit disloctions
;
YBa2Cu3O7 films
;
step-edge junction
;
HREM
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The atomic structure of 90° [100] (or [010]) tilt grain boundaries in YBa2Cu3O7 thin-film step-edge junctions and, for comparison, in the interface between a-axis and c-axis oriented YBa2Cu3O7 grains is investigated by means of high-resolution transmission electron microscopy. For (100)(001)-type boundaries two different structures are found. In the first a (001) CuO2 plane of one grain faces a (100) Y−Ba−O plane of the other grain, in the second a (001) BaO plane faces a (100) Cu−O plane. In the former structure an incomplete unit cell of YBa2Cu3O7 terminates at the boundary and a smaller strain in the adjacent CuO2 planes is detected in comparison with the latter. It is found that a combination of a partial dislocation with a “124” stacking fault is a way to accommodate the lattice mismatch between c and 3a of YBa2Cu3O7 in the boundary. For a symmetric (103)(103)-type boundary a displacement of the Cu-atoms of the CuO2 planes is found near the boundary plane. From this a redistribution of the oxygen atoms around the Y-atoms located right in the boundary plane is inferred. The possible effect of the boundary structure on the superconducting properties of YBa2Cu3O7 films is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00188700
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