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Title: Syntheses and properties of {kappa}-phase organic superconductors

Syntheses and properties of {kappa}-phase organic superconductors The syntheses and physical properties of {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]X (X=Br and Cl) are summarized. The {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br salt is the highest {Tc} radical-cation based ambient pressure organic superconductor ({Tc}=11.6 K), and the {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl salt becomes a superconductor at even higher {Tc} under 0.3 kbar hydrostatic pressure ({Tc}=12.8 K). The similarities and differences between {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br and {kappa}-(ET){sub 2}Cu(NCS){sub 2} ({Tc}=10.4 K) are presented. The X-ray structures at 127 K reveal that the the S{hor_ellipsis}S contacts shorten between ET dimers in the former compound while the S{hor_ellipsis}S contacts shorten within dimers in the latter. The difference in their ESR linewidth behavior is also explained in terms of the structural differences. A semiconducting compound, (ET)Cu[N(CN){sub 2}]{sub 2}, isolated during {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl synthesis is also reported. The ESR measurements of the {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl salt indicate that the phase transition near 40 K is similar to the spin density wave transition in (TMTSF){sub 2}SbF{sub 6}. A new class of organic superconductors, {kappa}-(ET){sub 2}Cu{sub 2}(CN){sub 3} and {kappa}-(ET){sub 2}Cu{sub 2}(CN){sub 3}-{delta}Br{delta}, is reported with {Tc}`s of 2.8 K (1.5 kbar) and 2.6 K (1 kbar), respectively.
Authors: ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
OSTI Identifier:10111832
Report Number(s):SAND--91-2826C; ANL/CP--75045; CONF-911202--8
ON: DE92004353; TRN: 92:003021
DOE Contract Number:AC04-76DP00789; W-31109-ENG-38
Resource Type:Conference
Resource Relation:Other Information: PBD: [1991]
Research Org:Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org:USDOE, Washington, DC (United States)
Country of Publication:United States
Language:English
Subject: 36 MATERIALS SCIENCE; ORGANIC SUPERCONDUCTORS; BROMINE COMPOUNDS; CHLORINE COMPOUNDS; TRANSITION TEMPERATURE; ELECTRIC CONDUCTIVITY 360607; 360606; 360601