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Neutron scattering investigations into high-temperature superconductors; Neutronenstreuuntersuchungen an Hochtemperatur-Supraleitern

Technical Report:

Abstract

The perovskite-type high-{Tc} compounds RBa{sub 2}Cu{sub 3}O{sub x} (R=Y, most rare earths, except Ce and Tb) does not exhibit superconductivity. Until today there is no generally accepted explanation for the unusual behaviour of the Pr system. The suppression of superconductivity in the RBa{sub 2}Cu{sub 3}O{sub 7} compound is related to an electronic change which should also influence the structural parameters. To check this assumption, a systematic low temperature neutron-diffraction study was made of the RBa{sub 2}Cu{sub 3}O{sub x} (R=Y and rare earth; x=7 and 6.1) compounds. Comparison of various interatomic distances in function of the radius of the trivalent rare earths exhibit the well known lanthanide contraction with the exception of the bond lengths of Pr-O(2), Cu(2)-Cu(2) and Cu(2)-O(3) in PrBa{sub 2}Cu{sub 3}O{sub 7} which are much shorter compared to the other lanthanide compounds. This shortening of the bond lengths must be related to suppression of superconductivity in PrBa{sub 2}Cu{sub 3}O{sub 7}. This tendency was also observed for the Er{sub 1-y}Pr{sub y}Ba{sub 2}Cu{sub 3}O{sub x} system. Furthermore structure analyses show a critical buckling angle in the CuO{sub 2} planes: if the buckling is larger than a critical value of 167.3{sup o}, superconductivity is destroyed. In fast neutron irradiated ErBa{sub 2}Cu{sub  More>>
Authors:
Guillaume, M [1] 
  1. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Publication Date:
Oct 01, 1994
Product Type:
Technical Report
Report Number:
LNS-174
Reference Number:
SCA: 360202; 360207; PA: AIX-26:007992; EDB-95:008580; SN: 95001301010
Resource Relation:
Other Information: DN: Dissertation ETH-Zurich.; PBD: Oct 1994
Subject:
36 MATERIALS SCIENCE; HIGH-TC SUPERCONDUCTORS; CRYSTAL STRUCTURE; SUPERCONDUCTIVITY; RARE EARTH COMPOUNDS; BARIUM OXIDES; CALCIUM OXIDES; COPPER OXIDES; EXPERIMENTAL DATA; GADOLINIUM 160; NEUTRON DIFFRACTION; SAMARIUM 154; YTTRIUM OXIDES; 360202; 360207; STRUCTURE AND PHASE STUDIES
OSTI ID:
10104405
Research Organizations:
Eidgenoessische Technische Hochschule, Zurich (Switzerland). Lab. fuer Neutronenstreuung
Country of Origin:
Switzerland
Language:
German
Other Identifying Numbers:
Other: ON: DE95610881; TRN: CH9400371007992
Availability:
OSTI; NTIS; INIS
Submitting Site:
CHN
Size:
137 p.
Announcement Date:
Jun 30, 2005

Technical Report:

Citation Formats

Guillaume, M. Neutron scattering investigations into high-temperature superconductors; Neutronenstreuuntersuchungen an Hochtemperatur-Supraleitern. Switzerland: N. p., 1994. Web.
Guillaume, M. Neutron scattering investigations into high-temperature superconductors; Neutronenstreuuntersuchungen an Hochtemperatur-Supraleitern. Switzerland.
Guillaume, M. 1994. "Neutron scattering investigations into high-temperature superconductors; Neutronenstreuuntersuchungen an Hochtemperatur-Supraleitern." Switzerland.
@misc{etde_10104405,
title = {Neutron scattering investigations into high-temperature superconductors; Neutronenstreuuntersuchungen an Hochtemperatur-Supraleitern}
author = {Guillaume, M}
abstractNote = {The perovskite-type high-{Tc} compounds RBa{sub 2}Cu{sub 3}O{sub x} (R=Y, most rare earths, except Ce and Tb) does not exhibit superconductivity. Until today there is no generally accepted explanation for the unusual behaviour of the Pr system. The suppression of superconductivity in the RBa{sub 2}Cu{sub 3}O{sub 7} compound is related to an electronic change which should also influence the structural parameters. To check this assumption, a systematic low temperature neutron-diffraction study was made of the RBa{sub 2}Cu{sub 3}O{sub x} (R=Y and rare earth; x=7 and 6.1) compounds. Comparison of various interatomic distances in function of the radius of the trivalent rare earths exhibit the well known lanthanide contraction with the exception of the bond lengths of Pr-O(2), Cu(2)-Cu(2) and Cu(2)-O(3) in PrBa{sub 2}Cu{sub 3}O{sub 7} which are much shorter compared to the other lanthanide compounds. This shortening of the bond lengths must be related to suppression of superconductivity in PrBa{sub 2}Cu{sub 3}O{sub 7}. This tendency was also observed for the Er{sub 1-y}Pr{sub y}Ba{sub 2}Cu{sub 3}O{sub x} system. Furthermore structure analyses show a critical buckling angle in the CuO{sub 2} planes: if the buckling is larger than a critical value of 167.3{sup o}, superconductivity is destroyed. In fast neutron irradiated ErBa{sub 2}Cu{sub 3}O{sub 7} samples (this treatment decreases {Tc}) we also observed a tendency towards this critical value. Indeed, for PrBa{sub 2}Cu{sub 3}O{sub 7} we found the buckling angle to be above the critical value. By means of inelastic neutron scattering we were able to show that the superconductivity in the mixed Er{sub 1-y}Pr{sub y}Ba{sub 2}Cu{sub 3}O{sub x} system is only locally destroyed by the Pr ions, and their influence on the crystalline electric field at the Er site can be explained by a small structural distortion. (author) figs., tabs., refs.}
place = {Switzerland}
year = {1994}
month = {Oct}
}