Unusual behavior in the upper critical magnetic fields of the ambient-pressure organic superconductor. kappa. -(BEDT-TTF) sub 2 Cu(N(CN) sub 2 )Br (where BEDT-TTF represents bis(ethylenedithio) tetrathiofulvalene)

Journal Article · Wed Oct 31 23:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.8686· OSTI ID:6360073

Kwok, W K; Welp, U; Carlson, K D; Crabtree, G W; Vandervoort, K G; Wang, H H; Kini, A M; Williams, J M; Stupka, D L; Montgomery, L K; Thompson, J E ^[1]

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1. Materials Science Division, Argonne National Laboratory, Argonne, IL (USA) Chemistry Divisions, Argonne National Laboratory, Argonne, IL (USA)

We report a determination of the temperature dependence of the upper critical magnetic fields {ital H}{sub {ital c}2} for {kappa}-(BEDT-TTF){sub 2}Cu(N(CN){sub 2})Br, with the use of dc-magnetization measurements that show a well-defined diamagnetic onset. We find large slopes of {minus}20 T/K and {minus}2.2 T/K for {bold H}{parallel}{ital ac} and {bold H}{parallel}{ital b}, respectively, which lead to coherence lengths of 37 and 4 A. There is unusual structure in the critical fields and a possible dimensional crossover at {ital T}/{ital T}{sub {ital c}}{approximately}0.97 for {bold H}{parallel}{ital ac}. Neither the slopes nor the structure are observable in the superconducting transition measured by ac magnetoresistance, which exhibits strong magnetic-field broadening similar to that of the high-{Tc} copper oxide superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. We find a strong depression of {ital T}{sub {ital c}}, as large as 1.2 K, when the sample is rapidly cooled.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6360073
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:13; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
BEDT-TTF
COPPER COMPOUNDS
CRITICAL FIELD
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HETEROCYCLIC COMPOUNDS
MAGNETIC FIELDS
MAGNETIZATION
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANIC SUPERCONDUCTORS
PHYSICAL PROPERTIES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
ULTRALOW TEMPERATURE