C. W. Mayer

Low temperature measurements of the electrical conductivities of some charge transfer salts with the asymmetric donors MDT-TTF, EDT-TTF and EDT-DSDTF. (MDT-TTF)2AuI2, a new superconductor (Tc=3.5 K at ambient pressure)

Abstract The electrical and x-ray structural properties of the new superconductor (MDT-TTF) 2 AuI 2 with a T c of 3.5 K at ambient pressure were studied (MDT-TTF = methylenedithio-tetrathiafulvalene). Low temperature measurements of the electrical conductivities of two new metals, (EDT-TTF) 2 IBr 2 and (EDT-DSDTF) 2 AuI 2 are reported (EDT-TTF = ethylenedithio-tetrathiafulvalene, EDT-DSDTF = ethylenedithio-diselenadithiafulvalene).

Shubnikov-de Haas oscillations and magnetoresistance in the semi-metallic state of (TSeT)2Cl

Abstract Measurements of the magnetoresistance of the tetraselenotetracene derivatives (TSeT) 2 Cl and (TSeT) 2 Br have been performed at temperatures between 1.4 and 6 K in magnetic fields up to 15 T. At 1.4 K Schubnikov-de Haas oscillations have been observed for fields higher than 4 T in (TSeT) 2 Cl single crystals, indicative of the existence of small hole pockets, as suggested formerly. From the zero-field resistance of the low-temperature semi-metallic state and from the field action, it is deduced that (TSeT) 2 Cl and (TSeT) 2 Br probably exhibit the Kondo effect.

Structural and electrical properties of some cation radical salts based on EDTTTF, PEDTTTF, and similar π-donors

Abstract The X-ray structural and electrical properties of some cation radical salts of the type D n X [where D=ethylenedithiotetrathiafulvalene (EDTTTF), pyrazinoethylenedithiotetrathiafulvalene (PEDTTTF), methylenedithiotetrathiafulvalene (MDTTTF), pyrazinoethylenedithiodiselenadithiafulvalene (PEDTDSDTF), ethylenedithiodiselenadithiafulvalene (EDTDSDTF), [4,5-b] pyridinodithiotetrathiafulvalene ([4,5-b]PEDTTTF), dimethylethylenedithiotetrathiafulvalene (DMEDTTTF), bis(ethylenedithio) tetrathiafulvalene (BEDTTTF); X=I 3 , IBr 2 , AuI 2 , BF 4 , ClO 4 , PF 6 , etc; n=1,2…] were studied.

ESR study of κ-D4H4(BEDTTTF)2Cu(SCN)2 molecular superconductor

Abstract We have investigated the magnetic properties of the κ-phase molecular superconductor (BEDTTTF) 2 Cu(SCN) 2 partially or totally deuteriated. By ESR spectroscopy we have evidenced the linewidth and g factor temperature dependences in the metallic state above the transition temperature ( T c = 9−10 K). We have also confirmed by the Meissner effect the presence of a strong and inverse isotope effect of these SC salts. A discussion in relation to the influence of electronic localization on both the magnetic and transport properties in the conducting state and the appearance of the SC state in these lamellar type compounds has been developed.

Conducting and Superconducting Salts Based on Some Symmetrical and Unsymmetrical Donors

Conducting and superconducting salts based on bis(ethylenedithio)tetrathiafulvalene, ehtylenedithioselenatrithiafulvalene, ethylenedioxyethylenedithiotetrathiafulvalene, and ethylenedioxyvinylenedithiotetrathiafulvalene were prepared and studied.

Conducting and Superconducting Crystals Based on Some Unsymmetrical Donor Molecules

Recently, a number of conducting and superconducting salts based on unsym-metrical π-donor molecules have been prepared and studied (see [1–5]). In this paper the preparations, crystal structures and physical properties of some salts based on the unsymmetrical π-donors ethylenedioxyethylenedithiotetrathiafulvalene (1), ethylenedioxymethylenedithiotetrathiafulvalene (2), ethylenedioxyvinylenedithiotetrathiafulvalene (3) and methylenedithiotetrathiafulvalene (4) are described.

Low temperature semi-metallic state in organic metals (TSeT)2Cl and (TSeT)2Br

Abstract Magnetoresistance measurements have been carried out on (TSeT) 2 X (X = Cl; Br) crystals in the magnetic field up to 15T at temperatures between 1.4K and 6K. For X = Cl Shubnikov-de Haas oscillations have been observed at H ⩾ 4 T; T ⩽ 4.2 K, indicative of the existence of small pockets at the Fermi surface, as suggested formerly.