𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Evidence against hole formation by Ca in YBa2Cu4O8

✍ Scribed by M. Knupfer; N. Nücker; M. Alexander; H. Romberg; P. Adelmann; J. Fink; J. Karpinski; E. Kaldis; S. Rusiecki; E. Jilek

Publisher
Elsevier Science
Year
1991
Tongue
English
Weight
391 KB
Volume
182
Category
Article
ISSN
0921-4534

No coin nor oath required. For personal study only.

✦ Synopsis

We report on electron energy-loss studies of Ca-doped YBa2Cu4Os. O I s and Ca 2p absorption edges indicate that there is almost no change of the hole concentration upon Ca doping and that a major fraction of the Ca enters the Ba site. This suggests that the increase of Tc upon Ca doping is not caused by a formation of additional holes as expected for the replacement of trivalent Y by divalent Ca.

📜 SIMILAR VOLUMES

Raman spectra of Ca substituted YBa2Cu4O
Raman spectra of Ca substituted YBa2Cu4O8
✍ Y. Kodama; S. Tanemura; T. Ikeda 📂 Article 📅 1991 🏛 Elsevier Science 🌐 English ⚖ 213 KB

Raman spectra of Yl-xCaxBa2Cu408 were investigated. At the Ca concentraiton of 10 %, which was solubility limit, frequency shift of 2 cm -1 was observed in the peaks at 492 cm -1 and 595 cm "1 assigned to the motion of 0(1) and 0(4) atoms, respectively. It is suggested that the stractural change due

Specific heat and penetration depths of
Specific heat and penetration depths of YBa2Cu4O8 and YBa1.8Ca0.2Cu4O8 near Tc
✍ A. Schilling; H.R. Ott; J.D. Guo; S. Rusiecki; J. Karpinski; E. Kaldis 📂 Article 📅 1991 🏛 Elsevier Science 🌐 English ⚖ 244 KB

Specific-heat data around the critical temperature Tc = 90 K of polycrystalline YBal 8Cao 2Cu408 show a discontinui\_ty ACp/Tc = 22 mJ/mol K z. In undoped YBa2Cu408 and in YBa2Cu307,'the corresponding anomalies are 15 mJ/mol K z and 55 mJ/mol K z. The in-plane London penetration depthoof the Ca-dope