Grain boundaries in high Tc materials: transport properties and structure

AbstractA comprehensive understanding of the transport properties of interfaces in high-Tc cuprates been obtained by considering their microstructure, the possibility of bending of the electronic band structure in these materials, and the predominant dx2-y2 -symmetry of the order parameter in most high-Tc cuprates. These factors are of central importance for the critical current density and the normal state resistivity of grain boundaries and their dependencies on boundary misorientation and on applied magnetic and electrical fields. In addition, some of these factors play an important role for the transport properties of other interfaces involving high-Tc superconductors, such as superconductors-normal metal contacts.Based on the improved understanding of the mechanisms controlling interface transport properties, we have been able to meet a long-standing challenge in high-Tc superconductivity and have increased the critical current densities of grain boundaries by large factors, using appropriate doping.

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Dilatation stresses and transport properties of grain boundaries in high-TC superconductors

Materials Science and Engineering A ◽

10.1016/s0921-5093(01)01136-4 ◽

2001 ◽

Vol 313 (1-2) ◽

pp. 207-217 ◽

Cited By ~ 8

Author(s):

I.A. Ovid'ko

Keyword(s):

Grain Boundaries ◽

Transport Properties ◽

High Tc Superconductors ◽

High Tc

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High Resolution Electron Microscopy of internal interfaces in layered materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174734 ◽

1990 ◽

Vol 48 (4) ◽

pp. 320-321

Author(s):

Yoichi Ishida ◽

Hideki Ichinose ◽

Yutaka Takahashi ◽

Jin-yeh Wang

Keyword(s):

Grain Boundaries ◽

Mirror Symmetry ◽

Functional Materials ◽

High Resolution Electron Microscopy ◽

Layered Materials ◽

Plane Boundary ◽

Chemical Information ◽

Layer Plane ◽

High Tc ◽

Cubic Metals

Layered materials draw attention in recent years in response to the world-wide drive to discover new functional materials. High-Tc superconducting oxide is one example. Internal interfaces in such layered materials differ significantly from those of cubic metals. They are often parallel to the layer of the neighboring crystals in sintered samples(layer plane boundary), while periodically ordered interfaces with the two neighboring crystals in mirror symmetry to each other are relatively rare. Consequently, the atomistic features of the interface differ significantly from those of cubic metals. In this paper grain boundaries in sintered high-Tc superconducting oxides, joined interfaces between engineering ceramics with metals, and polytype interfaces in vapor-deposited bicrystal are examined to collect atomic information of the interfaces in layered materials. The analysis proved that they are not neccessarily more complicated than that of simple grain boundaries in cubic metals. The interfaces are majorly layer plane type which is parallel to the compound layer. Secondly, chemical information is often available, which helps the interpretation of the interface atomic structure.

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