Title :
UV-light irradiation effects on oxide superconducting thin films
Author :
Enokihara, A. ; Kohiki, S. ; Higashino, H. ; Setsune, K. ; Wasa, K.
Author_Institution :
Matsushita Electr. Ind. Co. Ltd., Osaka, Japan
fDate :
3/1/1991 12:00:00 AM
Abstract :
Bi2Sr2CaCu2Ox thin films prepared on (100) MgO substrates by RF magnetron sputtering were irradiated with ultraviolet (UV) light in He gas of about 500 Pa using a low-pressure mercury lamp. The zero-resistance temperature and the critical current density were gradually decreased with irradiation time. X-ray photoemission spectra showed that the mean Cu valence of the film was decreased approximately from +2 to +1 by the irradiation, while the valence of Bi ions was not changed. These results imply that the UV irradiation selectively reduces Cu ions and that the superconductivity strongly depends on the Cu valence
Keywords :
X-ray photoelectron spectra; bismuth compounds; calcium compounds; critical current density (superconductivity); high-temperature superconductors; radiation effects; sputtered coatings; strontium compounds; superconducting thin films; superconducting transition temperature; 500 Pa; Bi2Sr2CaCu2Ox; He gas; RF magnetron sputtering; UV-light irradiation effects; X-ray photoemission spectra; critical current density; high temperature superconductor; mean Cu valence; zero-resistance temperature; Bismuth; Helium; Lamps; Radio frequency; Sputtering; Strontium; Substrates; Superconducting magnets; Superconducting thin films; Temperature;
Journal_Title :
Magnetics, IEEE Transactions on
