Title :
YBCO films deposited on YAlO/sub 3/ substrates: microstructure and transport properties
Author :
Dubourdieu, C. ; Sénateur, J.P. ; Thomas, O. ; Weiss, F. ; Hensen, S. ; Müller, G.
Author_Institution :
Lab. des Mater. et du Genie Phys., UMR, St. Martin d´´Heres, France
fDate :
6/1/1997 12:00:00 AM
Abstract :
Epitaxial YBa2Cu3O7-x, (YBCO) thin films have been grown by Metal Organic Chemical Vapor Deposition on YAIO3 (001) substrates. YAIO3 has suitable dielectric properties for microwave applications. A particular twinning geometry has been evidenced on this substrate. The twinning directions [110] and [1Ī0] of YBCO are aligned along the [OlO] direction of YAIO3. This epitaxial relationship can be explained by lattice strain considerations. The microwave surface impedance has been measured at 87 GHz between 4.2 K and 150 K using a resonant copper cavity. The best film exhibits a surface resistance of 4 3 mω at 7 7 K and 87 GHz and a residual surface resistance of 3 mΩ at 4.2 K.
Keywords :
barium compounds; high-temperature superconductors; superconducting epitaxial layers; surface conductivity; twinning; vapour phase epitaxial growth; yttrium compounds; 4.2 to 150 K; 87 GHz; MOCVD; YAlO/sub 3/; YAlO/sub 3/ substrates; YBa/sub 2/Cu/sub 3/O/sub 7/; dielectric properties; epitaxial YBa/sub 2/Cu/sub 3/O/sub 7-x/ films; high temperature superconductor; microstructure; microwave surface impedance; residual surface resistance; transport properties; twinning geometry; Chemical vapor deposition; Dielectric substrates; Dielectric thin films; Geometry; Lattices; Organic chemicals; Sputtering; Strain measurement; Surface resistance; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
