Thin film Hg-based superconductors, thermoelectric materials and methods of fabrication thereof

Abstract

Improved Hg-containing superconducting films and thermoelectric materials are provided. The films are fabricated by annealing starting T1-containing films (e.g., T1-1212 or T1-2212) in an Hg-vapor environment so as to cause a substitution of T1 by Hg without substantial alteration of the crystalline structure of the starting films. Preferably, a body comprising a substrate having an epitaxial T1-containing film thereon is annealed under vacuum conditions with a Hg-based bulk; typical annealing conditions are 600-900° C. for a period of from about 1-20 hours. The final Hg-containing film products have a J c of at least about 10 6 A/cm 2 (100 K, OT) and a X min of up to about 50%. The thermoelectric materials are prepared by perturbing a crystalline precursor having a structure similar to the final material so as to cause a first molecule to be released from the precursor. A vapor is introduced into the reaction system simultaneous to or shortly after the perturbation step so as to cause molecules which are within the vapor and are different than the first molecules to replace the first molecules in the precursor.

We claim:  
     
         1 . An Hg-1212 epitaxial film superconductor having a J c  of at least about 10 6  A/cm 2  at 100K and zero magnetic field.  
     
     
         2 . The film of  claim 1 , said film having a thickness of from about 0.005-500 μm.  
     
     
         3 . The film of  claim 2 , said thickness being from about 0.1-1 μm.  
     
     
         4 . The film of  claim 1 , said film being HgBa 2 CaCu 20 x where x ranges from about 5.8-6.2.  
     
     
         5 . An Hg-containing epitaxial film superconductor having a X min  of up to about 50%.  
     
     
         6 . The film of  claim 5 , said film having a thickness of from about 0.005-500 μm.  
     
     
         7 . The film of  claim 6 , said thickness being from about 0. 1-1 μm.  
     
     
         8 . The film of  claim 5 , said film being HgBa 2 CaCu 30 x where x ranges from about 7.8-8.2.  
     
     
         9 . The film of  claim 5 , said film having a J c  of at least about 10 6  A/cm 2  at 100K and zero magnetic field.  
     
     
         10 . An Hg-containing epitaxial film superconductor having a transport J c  of at least about 10 6  A/cm 2  at 100K and zero magnetic field.  
     
     
         11 . The film of  claim 10 , said film having a thickness of from about 0.005-500 μm.  
     
     
         12 . The film of  claim 11 , said thickness being from about 0.1-1 μm.  
     
     
         13 . The film of  claim 10 , said film having a transport J c  of at least about 2×10 6  A/cm 2  at 100K and zero magnetic field.  
     
     
         14 . The film of  claim 13 , said film having a transport J c  of at least about 2.3×10 6  A/cm 2  at 100K and zero magnetic field.  
     
     
         15 . The film of  claim 10 , said film being in the form of micro-bridges having a width of from about 2-10 μm.  
     
     
         16 . The film of  claim 15 , said film micro-bridges having a transport J c  of at least about 2.3×10 6  A/cm 2  at 100K and zero magnetic field.  
     
     
         17 . An Hg-containing epitaxial film superconductor having a microwave surface resistance of less than about 0.4 mΩ at 120K.  
     
     
         18 . The film of  claim 17 , said film being an Hg-1212 film.