Method for preparing atomistically straight boundary junctions in high temperature superconducting oxides

• US 7,320,732 B2
• Filed: 07/27/2005
• Issued: 01/22/2008
• Est. Priority Date: 01/31/2003
• Status: Expired due to Fees

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Chan, Siu-Wai
• Primary Examiner(s): Kunemund; Robert
• Assistant Examiner(s): Chaet; Marissa W.
• Application Number:
  US11/190,699
• Publication Number:
  US 20070020894A1
• Time in Patent Office: 909 Days
• Field of Search: 117/1, 257/1, 438/1
• US Class Current: 117/101
• CPC Class Codes: H10N 60/0576 characterised by the substrate
• CPC Class Codes: H10N 60/0941 comprising high-Tc ceramic materials
• CPC Class Codes: H10N 60/203 comprising high-Tc ceramic materials

Abstract

A method for preparing film oxides deposited on a substrate with a resulting grain boundary junction that is atomistically straight. A bicrystal substrate having a straight grain boundary is prepared as a template. The Miller indices h1, k1, h2, k2 of the two grains of the substrate are chosen such that the misorientation angle of the film is equal to arctan k1/h1+arctan k2/h2. The film is grown on the substrate using a layer-by-layer growth mode.

Claims

1. A method of forming an atomistically straight grain boundary in a bicrystal epitaxial film formed on a surface of a substrate, comprising the steps of:

(a) preparing a bicrystal substrate having a straight grain boundary as a template, wherein the misorientation angle of a first and a second crystal of the bicrystal substrate is equal to;

arctan k₁/h₁+arctan k₂/h₂, where h₁ and k₁ are the Miller indices of a first grain of the bicrystal substrate and h₂ and k₂ are the Miller indices of a second grain of the bicrystal substrate; and

(b) depositing the film on the substrate using a layer-by-layer growth mode so that the boundary between the grains of the film is atomistically straight.

2. The method according to claim 1, wherein said layer-by-layer growth mode of the film is achieved by solution coating.

3. The method according to claim 1, wherein said layer-by-layer growth mode of the film is achieved by liquid phase epitaxy.

4. The method according to claim 1, wherein said layer-by-layer growth mode of the film is achieved by molecular beam epitaxy.

5. The method according to claim 1, wherein the layer-by-layer growth mode of the film is achieved by chemical vapor deposition.

6. The method according to claim 1, wherein said film is a high temperature super-conducting oxide film.

7. The method according to claim 1, wherein said film is a yttrium barium copper oxide.

8. The method according to claim 1, wherein said film is a bismuth calcium strontium copper oxide.

9. The method according to claim 1, wherein said substrate is a strontium titanium oxide.

10. The method according to claim 1, wherein absolute values of the Miller indices h₁, k₁, h₂, k₂ are each less than or equal to 5.

11. The method according to claim 1, wherein said film is deposited layer-by-layer stoichiometrically.

12. The method according to claim 1, wherein said film is deposited with a layer thickness less than 1 μ

m.