Laser ablation and deposition of high Tc superconducting BiSrCaCuO films doped with lead, praseodymium and lithium

✍ Scribed by J. Levoska; T. Murtoniemi; S. Leppävuori

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 339 KB
• Volume: 13
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/0921-5107(92)90101-e

✦ Synopsis

High T~ superconducting Bi-Sr-Ca-Cu-O thin films doped with lead, praseodymium and lithium were ablated on MgO(100) substrates at room temperature using a neodymium-doped yttrium aluminium garnet laser at 1064 nm. The effect of annealing conditions on the structural and superconducting properties of the films was investigated. The leaddoped films with [Bi]:[Sr]:[Ca]:[Cu] ratio near 2:2:2:3 annealed for 60 h at 850 °C consisted mainly (above 85%) of the 2: 2: 2: 3 phase. These films had a To0 above 100 K. The films doped with praseodymium or with praseodymium and lead had poorer superconducting properties than the undoped films do. It was observed that both praseodymium and lithium inhibited the formation of the 2 : 2: 2 : 3 phase. For lithium-doped films with [Bi]:[Sr]:[Ca]:[Cu] ratios near 2 : 2 : 1 : 2 or 2:2:2:3, T~0 values in the range 83-85 K were obtained. This was an enhancement of 3-6 K compared with the values for the undoped 2: 2:1 : 2 phase films prepared under similar conditions. For the best lithium-doped films, critical currents exceeding 104 A cm -2 at 77 K were measured.