Title :
In situ growth and properties of epitaxial TlBa/sub 2/CaCu/sub 2/O/sub 7/ and TlBa/sub 2/(Ca/sub 1-x/Y/sub x/)Cu/sub 2/O/sub 7/ thin films
Author :
Face, D.W. ; Nestlerode, J.P.
Author_Institution :
Du Pont Central Res. & Dev., Wilmington, DE, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
Epitaxial TlBa/sub 2/CaCu/sub 2/O/sub 7/ thin films have been grown on single-crystal LaAlO/sub 3/, NdGaO/sub 3/, and CeO/sub 2/ buffered sapphire substrates by in situ off-axis magnetron sputtering in the presence of Tl/sub 2/O vapor. Phase formation in this system has been investigated for substrate temperatures from 490 degrees C to 600 degrees C and deposition pressures from 50 mTorr to 300 mTorr. The effect of Tl/sub 2/O evaporation rate has also been studied. X-ray diffraction shows that films deposited under optimum conditions are highly epitaxial with the c-axis perpendicular to the substrate surface and
Keywords :
X-ray diffraction examination of materials; barium compounds; calcium compounds; high-temperature superconductors; sputter deposition; superconducting epitaxial layers; superconducting transition temperature; thallium compounds; vapour phase epitaxial growth; yttrium compounds; 490 to 600 degC; 50 to 300 mTorr; 71 to 91 K; Al/sub 2/O/sub 3/; CeO/sub 2/ buffered sapphire substrates; CeO/sub 2/-Al/sub 2/O/sub 3/; HTSC; LaAlO/sub 3/ substrate; NdGaO/sub 3/ substrate; Tl/sub 2/O vapor; TlBa/sub 2/(Ca/sub 0.6/Y/sub 0.4/)Cu/sub 2/O/sub 7/ films; TlBa/sub 2/(Ca/sub 0.8/Y/sub 0.2/)Cu/sub 2/O/sub 7/; X-ray diffraction; deposition pressures; epitaxial TlBa/sub 2/(Ca/sub 1-x/Y/sub x/)Cu/sub 2/O/sub 7/ thin films; epitaxial TlBa/sub 2/CaCu/sub 2/O/sub 7/ thin films; in situ off-axis magnetron sputtering; phase formation; smooth film surfaces; substrate temperatures; transition temperatures; High temperature superconductors; Nonhomogeneous media; Pressure control; Sputtering; Substrates; Superconducting films; Superconducting thin films; Superconducting transition temperature; Surface resistance; Thin film devices;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
