Specific heat of the ambient-pressure organic superconductor. beta. -di(bis(ethylenedithio)tetrathiafulvalene) triiodide (. beta. -(BEDT-TTF)/sub 2/I/sub 3/)

Journal Article · Sat Feb 01 04:00:00 EST 1986 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.33.2046· OSTI ID:6438955

Stewart, G R; O'Rourke, J; Crabtree, G W; Carlson, K D; Wang, H H; Williams, J M; Gross, F; Andres, K

We have measured the specific heat of single crystals of the ambient-pressure superconductor ..beta..-(BEDT-TTF)/sub 2/I/sub 3/, abbreviated ..beta..-(ET)/sub 2/I/sub 3/, from 0.7 to 18 K in zero and applied magnetic fields. No bulk specific-heat anomaly in the vicinity of T/sub c/ was observed, although Meissner-effect measurements (Hparallelc() performed on these same crystals yield a volume percent superconductivity of at least 25% at 0.8 K. We find a ..gamma.. = 24 +- 3 mJ/mol K/sup 2/, which is larger than the value for the only previously known ambient-pressure superconductor, the Se-based (TMTSF)/sub 2/ClO/sub 4/ (TMTSF denotes tetramethyltetraselenafulvalene). This difference is due primarily to the greater density of S atoms in ..beta..-(ET)/sub 2/I/sub 3/ compared to the density of Se atoms in (TMTSF)/sub 2/ClO/sub 4/. The response of the low-temperature specific heat to fields up to 10 T aligned along c( was 0 to +- 3%, in sharp contrast to previous reports of a 20% increase in the specific heat of (TMTSF)/sub 2/ClO/sub 4/ in a field of 2 T. No evidence for a high-field magnetic or insulating state similar to that observed in (TMTSF)/sub 2/ClO/sub 4/ was found for ..beta..-(ET)/sub 2/I/sub 3/. New results on the specific heat in applied fields for (TMTSF)/sub 2/ClO/sub 4/ are presented.

• Research Organization: Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6438955
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 33:3; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALKENES
BAND THEORY
CRYSTAL STRUCTURE
CRYSTALS
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY LEVELS
ETHYLENE
EXPERIMENTAL DATA
FERMI LEVEL
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INFORMATION
IODIDES
IODINE COMPOUNDS
LOW PRESSURE
MAGNETIC FIELDS
MONOCRYSTALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHYSICAL PROPERTIES
SPECIFIC HEAT
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TTF
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE