Title :
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
fDate :
6/1/2003 12:00:00 AM
Abstract :
Epitaxial c-axis-oriented HgBa2CaCu2O6+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 (Tc) 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 (Rs) values of ∼4 mΩ at 17.86 GHz and 77 K have been obtained. In comparison, films on sapphire substrates with Tc values up to 118 K showed critical current densities in the range of 0.7-1.0 MA/cm2 and Rs 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;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.812001
