Electronic property and structure of double-doping Y1−2xPrxCaxBa2Cu3O7−δ with 0 ⩽ x ⩽ 0.14

✍ Scribed by Yang Wang; Lei Shi; Songnan Chu

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 472 KB
• Volume: 470
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2010.05.238

✦ Synopsis

Equal amount Pr and Ca double-doping Y 1À2x Pr x Ca x Ba 2 Cu 3 O 7Àd with 0 6 x 6 0.14 have been investigated by X-ray diffraction, resistivity, and X-ray photoemission spectroscopy (XPS). The deviation of the linearly decreasing of T c vs. x curve was observed when x < 0.10. The resistivity and the temperature coefficient of resistivity also exhibit abnormal behaviors around x = 0.10. It is revealed that the conductivity behavior of Y 1À2x Pr x Ca x Ba 2 Cu 3 O 7Àd with low Pr content (x < 0.10) is different from that of the relative high Pr content (x > 0.10), which suggests a change of Pr valence with the Pr content. XPS measurement shows that the relative amount of Pr 3+ and Pr 4+ is closely related to the total Pr content x. The valence of Pr is close to +3 when x < 0.10 and increases towards +4 when x > 0.10, which implies a different mechanism for depression of superconductivity of Pr content x < 0.10 from that of Pr content x > 0.10 in Pr doping Y-123.