Title :
Surface morphology and critical current density of high quality YBa 2Cu3O7 thin films on sapphire substrates
Author :
In-Seon Kim ; Lim, Hae-Ryong ; Ho Kim, Dong ; Ki Park, Yong
Author_Institution :
Supercond. Group, Korea Res. Inst. of Stand. & Sci., Taejon, South Korea
fDate :
9/1/1999 12:00:00 AM
Abstract :
Pulsed laser deposition has been used to prepare YBa2Cu 3O7 (YBCO) film on CeO2 buffer layers on single crystal Al2O3 (11¯02) substrates. High quality YBCO films have been obtained when 500-Å-thick CeO 2 buffer layers were deposited with fluence of 1.5 J/cm2 and oxygen pressure of 50 mTorr. Surface morphology of the c-axis oriented YBCO films were strongly dependent on the preparation conditions of CeO2 buffer layers, resulting in significant changes of critical current densities. Critical current densities of YBCO films increased with the increase of the substrate temperature for CeO2 buffer layer deposition in the range 400°C⩽Ts⩽800°C. Superconducting properties in YBCO/CeO2/Al2O3 exhibit Tc=89.5 K, ΔTc⩽0.5 K, and Jc>3×106 A/cm2 at 77 K
Keywords :
barium compounds; cerium compounds; critical current density (superconductivity); high-temperature superconductors; pulsed laser deposition; sapphire; superconducting thin films; superconducting transition temperature; surface structure; yttrium compounds; 500 angstrom; 77 K; Al2O3; CeO2; CeO2 buffer layers; HTSC; YBa2Cu3O7; critical current density; high quality YBa2Cu3O7 thin films; oxygen pressure; preparation conditions; pulsed laser deposition; sapphire substrates; single crystal Al2O3; substrate temperature; superconducting properties; surface morphology; Buffer layers; Critical current density; Optical pulses; Pulsed laser deposition; Substrates; Superconducting epitaxial layers; Superconducting films; Surface morphology; Temperature distribution; Yttrium barium copper oxide;
Journal_Title :
Magnetics, IEEE Transactions on
