Doping and characterization of YBa2Cu3O7-delta thin films prepared by pulsed laser deposition

Citation
Ga. Farnan et al., Doping and characterization of YBa2Cu3O7-delta thin films prepared by pulsed laser deposition, SUPERCOND S, 14(3), 2001, pp. 160-167
Citations number
26
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
ISSN journal
09532048 → ACNP
Volume
14
Issue
3
Year of publication
2001
Pages
160 - 167
Database
ISI
SICI code
0953-2048(200103)14:3<160:DACOYT>2.0.ZU;2-3
Abstract
High-quality, smooth, optimally doped, c-axis thin films of YBa2Cu3O7-delta were grown on (001) MgO substrates by pulsed laser deposition and subseque nt oxygen annealing, They were characterized structurally by theta -2 theta and four-axis x-ray diffraction and, electrically, by a self-inductance me asurement, Through subsequent annealing in reduced pressure oxygen environm ents, underdoped films were produced and again characterized using the same techniques. The doping is reversible and reproducible. A monotonic decreas e of T-c and an increase of the c-axis length were found with a decrease of the oxygen partial pressure during the annealing. From these data correspo nding values of delta were determined. The width of the rocking curve of th e (005) peak was found to be substantially unchanged, at 0.28-0.29 degrees, between the optimally doped and the underdoped films. The relative peak in tensities showed a systematic variation with delta in agreement with model calculations by Ye and Nakamura. The grain alignment is exclusively along t he MgO high symmetry axes throughout the film. Resistance-temperature chara cteristics allowed the pseudogap onset temperature, T*, to be determined as a function of doping.