Oxide superconductor and method for producing same

• US 6,740,623 B2
• Filed: 01/24/2003
• Issued: 05/25/2004
• Est. Priority Date: 03/05/1999
• Status: Expired due to Fees

• Current Assignee: New Energy and Industrial Technology Development Organizatio
• Original Assignee: International Superconductivity Technology Center
• Inventors: Yamamoto, Ayako, Tajima, Setsuko, Hu, Wei-Zhi
• Primary Examiner(s): KOPEC, MARK T
• Application Number:
  US10/350,718
• Publication Number:
  US 20030144149A1
• Time in Patent Office: 487 Days
• Field of Search: 505/126, 505/776, 505/779
• US Class Current: 505/126
• CPC Class Codes: H10N 60/0268 of devices comprising copper oxide
• CPC Class Codes: H10N 60/857 comprising copper oxide
• CPC Class Codes: Y10S 505/776 Containing transition metal oxide with rare earth or alkaline earth
• CPC Class Codes: Y10S 505/779 Other rare earth, i.e. Sc,Y,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu and alkaline earth, i.e. Ca,Sr,Ba,Ra

Abstract

An Hg- or Nd-based oxide superconductor comprises Ba as a constituent element and has a content of carbon as an impurity at a level of not greater than 2.0 atomic % whereby the oxide superconductor stably shows high superconducting characteristics without causing degradation with time. For its production, BaO, which has a reduced content of carbon impurity of 0.5% or below, is provided as a feed stock for Ba, and the starting materials are mixed and processed in a dry atmosphere wherein an amount of a carbon-containing gas is suppressed to a certain level, thereby obtaining the oxide superconductor.

Claims

1. An oxide superconductor consisting of an oxide of the chemical formula

2. The oxide superconductor of claim 1, wherein the content of carbon is from 0.3 to 2.0 atomic %.

3. The oxide superconductor of claim 1, wherein the oxide has the chemical formula

4. The oxide superconductor of claim 1, wherein the content of carbon is not greater than 1.25 atomic %.