Many applications of high temperature superconductors (HTS) require high critical current densities and strong superconducting coupling across grain boundaries. It is well known that misorientated grain boundaries have an adverse effect on the performance in HTS devices. In order to resolve this issue, there is a need for a method of preparing thin film oxides on a substrate with atomistically straight boundary junctions. This technology describes a method which uses a bicrystal substrate having a straight grain boundary as a template. A film is deposited on the substrate using a layer-by-layer growth mode so that the boundary between the grains of the film is atomistically straight. The result is a uniform, straight boundary junction that reduces variability in superconductor performance.
When the main crystal axes in a superconductor are misaligned, this can adversely influence the critical current density. For example, a slight disorientation in boundary inclination can result in a significant decrease in critical current density. This technology addresses these issues with a method for making atomistically correct boundary planes. Thin film oxides are prepared with a bicrystal grain boundary to achieve completely straight planarity on a microscopic and atomistic level. Since the coupling of transport current across the boundary does not vary, this allows for a reproducible junction current and increased reliability of superconductor devices.
Patent Issued (US 7,320,732)
Available for licensing and sponsored research support
Tech Ventures Reference: IR M02-039
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