Low-temperature critical current of Y1−xCaxBa2Cu3O7−δ thin films as a function of hole content and oxygen deficiency

✍ Scribed by S.H. Naqib; Anita Semwal

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 211 KB
• Volume: 425
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2005.05.012

✦ Synopsis

The effects of hole content (p) and oxygen deficiency (d) on the zero-field critical current density, J c0 , were investigated for high-quality c-axis oriented Y 1Àx Ca x Ba 2 Cu 3 O 7Àd (x = 0, 0.05, 0.10, and 0.20) thin films. Ca was used to introduce hole carriers in the CuO 2 planes, independent of the oxygen deficiency in the CuO 1Àd chains. Low-temperature J c0 (16 K) of these films above the optimum doping were found to be high (>10 7 A/cm 2 ) and were primarily determined by the hole concentration, reaching a maximum at p $ 0.185 ± 0.005, irrespective of oxygen deficiency. This implies that oxygen disorder plays only a secondary role and the intrinsic J c0 is mainly governed by the carrier concentration and consequently by the superconducting condensation energy which also peaks at p $ 0.19 where the pseudogap correlation vanishes.