Structural instabilities in lanthanum cuprate superconductors

Journal Article · Fri Apr 01 00:00:00 EST 1994 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/BF00754942· OSTI ID:102566

Axe, J D ^[1]; Crawford, M K ^[2]

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1. Brookhaven National Lab., Upton, NY (United States)
2. DuPont, Wilmington, DE (United States)

Subtle but well characterized structural phase transformations occur at low temperatures in some lanthanum cuprate superconductors. These transformations, which involve collective tilting of the CuO{sub 6} octahedra, have a strong influence on superconducting and normal state properties. Experiments suggest that for a given hole doping the following hierarchy exists for superconductivity in these materials: T{sub c}(HTT)>T{sub c}(LTO)>T{sub c}(LTT), where HTT represents the untilted structure and LTO and LTT are the two limiting low temperature tilted structures. An additional very strong suppression of T{sub c}, suggestive of a competing electronic groundstate, occurs in the LTT phase for a hole to Cu ratio of 1/8. Neither of these effects are understood at present. This paper reviews both the evidence upon which these conclusions are based and some outstanding unanswered questions.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 102566
• Report Number(s): CONF-9309321-; ISSN 0022-2291; TRN: 95:019717
• Journal Information: Journal of Low Temperature Physics, Vol. 95, Issue 1-2; Conference: International workshop on cuprate and heavy fermion superconductors, Cologne (Germany), 27-30 Sep 1993; Other Information: PBD: Apr 1994
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LANTHANUM OXIDES
PHASE TRANSFORMATIONS
TRANSITION TEMPERATURE
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
CRYSTAL DOPING