Alkaline-earth layer high-temperature superconductivity

✍ Scribed by John D. Dow; Dale R. Harshman

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 92 KB
• Volume: 460-462
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2007.03.081

✦ Synopsis

Many experiments show that cuprate-planes are not needed for high-T c superconductivity. For example, doped Ba 2 YRuO 6 and Sr 2 YRuO 6 superconduct at T c $ 93 K and $49 K, have no cuprate-planes, and superconduct in their BaO and SrO planes. GdSr 2 -Cu 2 RuO 8 and Gd 2Àz Ce z Sr 2 Cu 2 RuO 10 superconduct in their SrO layers, despite having non-superconducting cuprate-planes. Muon spectroscopy of YBa 2 Cu 3 O 7 shows that its BaO layers superconduct, and its cuprate-planes do not. The superconductivity of YBa 2 Cu 3 O 7 is s-wave, not d-wave, once flux-pinning is corrected for. Photoemission and scanning tunneling microscopy measurements correctly show the importance of the cuprate-planes, but do not show their superconductivity. Superconductivity is detected by muon spectroscopy of YBa 2 Cu 3 O 7 and occupies the BaO layers, and not the cuprate-planes. Our work contradicts the cuprate-plane models of high-temperature superconductivity, and is fully consistent with specific heat and thermal conductivity measurements, which cuprate-plane models are not.