Tc enhancement and superconducting properties of a YBa2Cu3O∼6.5 thin film after fluorine insertion

✍ Scribed by O. Peña; M. Mokhtari; C. Perrin; C. Thivet; M. Guilloux-Viry; A. Perrin; M. Sergent

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 536 KB
• Volume: 206
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(93)90694-l

✦ Synopsis

An oxygen-deficient YBa2Cu3Ox thin film (Tc=54 K, ATe>8 K) was treated under a diluted (3e in N2) NF 3 gas flow at temperatures not exceeding 280°C. AC induction measurements show a substantial increase of Tc up to about 86 K and a clear improvement of the Z~,c dissipation component ( FWHM = 1.2 K ), as a function of the reaction time. The film was further studied at the end of the reaction by the AC-fleld dependence and by DC magnetization measurements, including ZFC/FC and magnetization cycles.

It was found that granular effects are not important, meaning that the crystalline properties of the film are not degraded by the fluorination process, in good agreement with the X-ray diffraction data. The sharpness of the X~c peak, the low Mrc/Mzrc ratio and the large hysteresis of the magnetization cycle indicate that the critical current densities are high (of the order of 106 A/cm 2 at 5 K) and comparable to reasonably good YBa2Cu307 thin films. The usefulness of the fluorination method and a comparison with halogenated YBa2CuaOx ceramics are also presented.