Grain-boundary structure of thin films of YBa2Cu3O7 and Bi2Sr2CaCu2O8 on bicrystalline substrates

Kabius, B.; Seo, Jin Won; Amrein, T.; Dähne, U.; Scholen, A.; Siegel, M.; Urban, K.; Schultz, L.

doi:10.1016/0921-4534(94)90151-1

Cited by 45 publications

(13 citation statements)

References 18 publications

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“…This is very similar to GB's in the cuprate superconductors, where the boundaries were also found to be clean without any secondary phases and with the lattice distortions to be confined within 1-2 lattice spacings. [37][38][39] However, the grain boundaries in doped manganite epitaxial films are almost as straight as the GB in the underlying SrTiO 3 bicrystal substrate. This is in clear contrast to GB's in 5. ͑a͒ Sketch of the junction model for grain boundary junctions in the doped manganites.…”

Section: B Model Considerationsmentioning

confidence: 99%

“…the cuprate superconductors that are strongly faceted. 38,39 It is very likely that this difference is related to the different growth modes of the cuprate and manganite thin films. Whereas the cuprates show a pronounced island growth with the islands growing across the substrate grain boundary resulting in strong faceting, the manganites show a molecular layer-by-layer growth mode.…”

Section: B Model Considerationsmentioning

confidence: 99%

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Low-frequency1/fnoise in doped manganite grain-boundary junctions

et al. 2002

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We have performed a systematic analysis of the low frequency 1/ f -noise in single grain boundary junctions in the colossal magnetoresistance material La 2/3 Ca 1/3 MnO 3−δ . The grain boundary junctions were formed in epitaxial La 2/3 Ca 1/3 MnO 3−δ films deposited on SrTiO 3 bicrystal substrates and show a large tunneling magnetoresistance of up to 300% at 4.2 K as well as ideal, rectangular shaped resistance versus applied magnetic field curves. Below the Curie temperature T C the measured 1/ f noise is dominated by the grain boundary. The dependence of the noise on bias current, temperature and applied magnetic field gives clear evidence that the large amount of low frequency noise is caused by localized sites with fluctuating magnetic moments in a heavily disordered grain boundary region. At 4.2 K additional temporally unstable Lorentzian components show up in the noise spectra that are most likely caused by fluctuating clusters of interacting magnetic moments. Noise due to fluctuating domains in the junction electrodes is found to play no significant role.

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Section: B Model Considerationsmentioning

confidence: 99%

Section: B Model Considerationsmentioning

confidence: 99%

Low-frequency1/fnoise in doped manganite grain-boundary junctions

et al. 2002

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“…High resolution transmission electron microscopy (HRTEM) revealed a strongly faceted grain boundary barrier with facets on a nanoscale [89]. This means that the macroscopic misorientation angles α 1 and α 2 of the grain boundary, which are determined by the bicrystal substrate, represent average values only.…”

Section: Transport Mechanism In Gbjsmentioning

confidence: 99%

Andreev bound states in high temperature superconductors

et al. 1998

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Abstract. Andreev bound states at the surface of superconductors are expected for any pair potential showing a sign change in different k-directions with their spectral weight depending on the relative orientation of the surface and the pair potential. We report on the observation of Andreev bound states in high temperature superconductors (HTS) employing tunneling spectroscopy on bicrystal grain boundary Josephson junctions (GBJs). The tunneling spectra were studied as a function of temperature and applied magnetic field. The tunneling spectra of GBJ formed by YBa2Cu3O 7−δ (YBCO), Bi2Sr2CaCu2O 8+δ (BSCCO), and La1.85Sr0.15CuO4 (LSCO) show a pronounced zero bias conductance peak that can be interpreted in terms of Andreev bound states at zero energy that are expected at the surface of HTS having a d-wave symmetry of the order parameter. In contrast, for the most likely s-wave HTS Nd1.85Ce0.15CuO4−y (NCCO) no zero bias conductance peak was observed. Applying a magnetic field results in a shift of spectral weight from zero to finite energy. This shift is found to depend nonlinearly on the applied magnetic field. Further consequences of the Andreev bound states are discussed and experimental evidence for anomalous Meissner currents is presented.

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“…[22][23][24][25] However, the boundary in the superconductor generally is not as simple. In this case, both the misorientation relationship and the macroscopic boundary plane in the bicrystal substrate can be predetermined with precision.…”

Section: Introductionmentioning

confidence: 99%

Faceting, dislocation network structure, and various scales of heterogeneity in a YBa₂Cu₃O_7−δ low-angle [001] tilt boundary

Tsu

Babcock

Kaiser³

1996

J. Mater. Res.

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The grain boundary topography and grain boundary dislocation network structure of a 6 ± [001] bicrystal of YBa 2 Cu 3 O 7-d were studied using diffraction-contrast transmission electron microscopy (TEM). Saw-tooth-shaped arrays of facets composed of facets with lengths of a few tens of nanometers were observed in each of two widely separated sections of the boundary. The facet planes were ͕110͖, ͕310͖, and ͕221͖. Further subfaceting of the (130) facets into a smaller-scale (a few nanometers) saw-tooth configuration of (010) and (110) facets produced a hierarchy of facets in at least one boundary section. The dislocation content observed in each type of facet agreed well with Frank's formula. However, the dislocations within individual facets frequently were inhomogeneously distributed, contrasting the picture of evenly spaced dislocations that is derived for boundaries of infinite extent. Certain types of dislocations repeatedly were grouped near the facet centers and ends. Well-separated partial dislocations frequently were observed near the facet midsections, but not near the facet junctions. Extended (ϳ30 nm) strain contrast was observed at all of the facet junctions formed by facets with dimensions on the order of tens of nanometers. This long-range strain may be due to the finite extent of the individual facets. These results all suggest that structural inhomogeneities occur on various length scales ranging from macroscopic to just a few nanometers. Such structural heterogeneity is consistent with the electrical heterogeneity that is indicated for many YBa 2 Cu 3 O 7-d grain boundaries.

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Grain-boundary structure of thin films of YBa2Cu3O7 and Bi2Sr2CaCu2O8 on bicrystalline substrates

Cited by 45 publications

References 18 publications

Low-frequency1/fnoise in doped manganite grain-boundary junctions

Low-frequency1/fnoise in doped manganite grain-boundary junctions

Andreev bound states in high temperature superconductors

Faceting, dislocation network structure, and various scales of heterogeneity in a YBa₂Cu₃O_7−δ low-angle [001] tilt boundary

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Grain-boundary structure of thin films of YBa2Cu3O7 and Bi2Sr2CaCu2O8 on bicrystalline substrates

Cited by 45 publications

References 18 publications

Low-frequency1/fnoise in doped manganite grain-boundary junctions

Low-frequency1/fnoise in doped manganite grain-boundary junctions

Andreev bound states in high temperature superconductors

Faceting, dislocation network structure, and various scales of heterogeneity in a YBa2Cu3O7−δ low-angle [001] tilt boundary

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Product

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Faceting, dislocation network structure, and various scales of heterogeneity in a YBa₂Cu₃O_7−δ low-angle [001] tilt boundary