Electronic structure and properties of isoelectronically substituted compounds Y{sub 1}Ba{sub 2-m}M{sub m}Cu{sub 3}O{sub 7} and Y{sub 1}Ba{sub 2-m}M{sub m}Cu{sub 4}O{sub 8} (M = Be, Mg, Ca, Sr, Ba, Ra)

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · Journal of Structural Chemistry

DOI:https://doi.org/10.1007/BF02578304· OSTI ID:114672

Ermakov, A I; Zharikova, E A; Markushin, N A ^[1]

---

1. D.I. Mendeleev Russian Chemical Engineering Univ. (Russian Federation)

According to cluster calculations, the electronic structures of compounds based on Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} and Y{sub 1}Ba{sub 2}Cu{sub 4}O{sub 8} with isoelectronically substituted barium have some qualitative distinctions. These compounds behave differently upon barium substitution by other elements due to differences in the character of their highest occupied and lowest unoccupied molecular orbitals. Substitution of barium by radium is expected to lead to an increase in oxygen stability without a significant decrease in the critical temperature of superconduction transition T{sub s}. In order to raise T{sub s}, it is of interest to study the systems YBa{sub 2-m}(Be or Mg){sub m}Cu{sub 3}O{sub x} and YBa{sub 2-m}(Ca, Sr){sub m}Cu{sub 3}O{sub x}. On partial substitution of barium by calcium in YBa{sub 2}Cu{sub 4}O{sub 8}, the mechanism of T{sub s} elevation may involve contraction of the forbidden band due to oxygen sublattice distortions in the vicinity of Ba centers.

• Sponsoring Organization: USDOE
• OSTI ID: 114672
• Journal Information: Journal of Structural Chemistry, Journal Name: Journal of Structural Chemistry Journal Issue: 2 Vol. 35; ISSN JSTCAM; ISSN 0022-4766
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
BERYLLIUM OXIDES
CALCIUM OXIDES
CHEMICAL COMPOSITION
COPPER OXIDES
ELECTRONIC STRUCTURE
HIGH-TC SUPERCONDUCTORS
MAGNESIUM OXIDES
STABILITY
STRONTIUM OXIDES
YTTRIUM OXIDES