Superconducting Hg-Ba-Ca-Cu-O thin films on lanthanum aluminate and sapphire substrates

Author

Stelzner, Thomas ; Schneidewind, Henrik ; Bruchlos, Gisela

Author_Institution

Inst. for Phys. High Technol., Jena, Germany

Volume

13

Issue

2

fYear

2003

fDate

6/1/2003 12:00:00 AM

Firstpage

2766

Lastpage

2768

Abstract

Epitaxial c-axis-oriented HgBa₂CaCu₂O_6+δ (Hg-1212) thin films have been prepared on lanthanum aluminate as well as on CeO₂ buffered r-plane sapphire substrates using a Tl-Hg cation-exchange process. Films on LaAlO₃ exhibited superconducting transition temperatures (T_c) up to 122 K and critical current densities in the range of 2.2-3.1 MA/cm² at 77 K and under self-field. For the microwave surface resistance (R_s) values of ∼4 mΩ at 17.86 GHz and 77 K have been obtained. In comparison, films on sapphire substrates with T_c values up to 118 K showed critical current densities in the range of 0.7-1.0 MA/cm² and R_s values of ∼7 mΩ. With further optimization of processing an improvement of superconducting properties of Hg-1212 films on sapphire substrates is expected.

Keywords

barium compounds; calcium compounds; critical current density (superconductivity); high-temperature superconductors; ion exchange; mercury compounds; superconducting epitaxial layers; superconducting transition temperature; surface resistance; 17.86 GHz; 77 K; Al₂O₃; CeO₂; CeO₂ buffer layer; Hg-Ba-Ca-Cu-O thin film; HgBa₂CaCu₂O₆; LaAlO₃; cation exchange process; critical current density; epitaxial growth; high temeperature superconductor; lanthanum aluminate substrate; microwave surface resistance; process optimization; sapphire substrate; self-field; superconducting transition temperature; Critical current density; High temperature superconductors; Lanthanum; Substrates; Superconducting films; Superconducting microwave devices; Superconducting thin films; Superconducting transition temperature; Surface morphology; Surface resistance;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2003.812001

Filename

1212194