US 7,981,840 B2 · Method of manufacturing Bi-based oxide superconductor thin films

Abstract

A well-crystallized a-axis (or b-axis) oriented Bi-based oxide superconductor thin film is manufactured in order to obtain a high performance layered Josephson junction using a Bi-based oxide superconductor. In manufacturing a well-crystallized a-axis oriented Bi-based oxide superconductor thin film, a (110) plane of a single crystal substrate of LaSrAlO4 or a vicinal cut substrate of a single crystal of LaSrAlO4 is used, on which an a-axis oriented Bi-2223 or Bi-2201 thin film is heteroepitaxially grown at a low film forming temperature T1, then homoepitaxially grown on the grown film at a high film forming temperature T2 (double temperature growth method). Although it is difficult to grow an a-axis oriented film directly on a substrate at a high temperature T2, an a-axis oriented Bi-2223 or Bi-2201 thin film is formed on the base by previously forming the base film at low deposition temperature.

Claims8

Dependent claims

A method of manufacturing a Bi-based oxide superconductor thin film having a c-axis parallel to a (110) or (10-10) crystal plane of a substrate and one of a-axis and b-axis being oriented perpendicular to the (110) or (10-10) crystal plane of the substrate, the method comprising the steps of:

depositing the oxide superconductor film on a vicinal substrate selected from the group consisting of LaSrAlO4, LaSrGaO4, α-Al2O3 and NdAlO3, while supplying oxygen, wherein the depositing includes
heteroepitaxially growing the one of a-axis and b-axis oriented oxide superconductor thin film at a first temperature, and then homoepitaxially growing the oxide superconductor thin film on the heteroepitaxially grown film at a second temperature which is higher than the first temperature,
wherein a lattice constant of the crystal plane of the superconductor thin film is an approximate integer multiple of a lattice constant of the crystal plane of the substrate and the oxide superconductor thin film is Bi2Sr2Ca2Cu3O10+X (where X is a positive number less than unity) or Bi2Sr2CuO6+Y (where Y is a positive number less than unity) thin film.

An oxide superconductor thin film deposited on a vicinal substrate having a c-axis parallel to a (110) or (10-10) crystal plane of a substrate and one of an a-axis and a b-axis being oriented perpendicular to the (110) or (10-10) crystal plane of the substrate,

wherein a lattice constant of a single crystal of the thin film is an approximate integer multiple of a lattice constant of a single crystal of the substrate, the vicinal substrate is selected from the group consisting of substrates of LaSrAlO4, LaSrGaO4, α-Al2O3, and NdAlO3, the superconductor thin film is Bi2Sr2Ca2Cu3O10+x, (where X is a positive number less than unity) or Bi2Sr2CuO6+Y (where Y is a positive number less than unity) thin film and which is manufactured such that the said thin film is heteroepitaxially grown at a first temperature, then homoepitaxially grown thereon at a second temperature which is higher than the said first temperature.

Dependencies are inferred from the claim text.

Method of manufacturing Bi-based oxide superconductor thin films

Life of this patent

Method of manufacturing Bi-based oxide superconductor thin films

Life of this patent

Abstract

Claims8