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Interlayer magnetoresistance of the Bechgaard salt (TMTSF)2NO3 is investigated up to 50 teslas under pressures of a few kilobars. This compound, the Fermi surface of which is quasi twodimensional at low temperature, is a semi metal under pressure. Nevertheless, a field-induced spin density wave is evidenced at 8.5 kbar above ∼ 20 T. This state is characterized by a drastically different spectrum of the quantum oscillations compared to the low pressure spin density wave state. PACS numbers: 75.30.Fv, 72.15.Gd, 71.18.+y Bechgaard salts (TMTSF) 2 X, where TMTSF stands for tetramethyltetraselenafulvalene and X is an inorganic anion, have been widely studied over the past twenty years for their very complex (pressure, magnetic field, temperature) phase diagrams that involve quasi-one dimensional (q-1D) metallic, spin density wave (SDW), superconducting and field-induced spin density wave (FISDW) states (for a review, see Refs.[1]). Nevertheless, FISDW phenomenon is still attracting experimental [2] and theoretical [3] studies. In the framework of the quantized nesting model [4] and its latest refinements [3], orbital effects stabilize SDW states in compounds with q-1D Fermi surface (FS) at low temperature through the increase of the 1D character of the electronic movement. Furthermore, it has also been stated that a FISDW can only occur provided the groundstate is superconducting [5]. In line with both of these predictions, a FISDW has so far only been observed in Bechgaard salts with both a superconducting groundstate and a q-1D FS, e. g. in slowly cooled (TMTSF) 2 ClO 4 at ambient pressure or (TMTSF) 2 PF 6 under pressures of a few kilobars. In contrast, a FISDW has also been reported in (DMET-TSF) 2 AuCl 2 which remains a q-1D metal at least down to 42 mK [6]. It should also be mentioned that a field-induced insulating phase, essentially driven by Pauli effects, has been evidenced in τ -phase organic metals with q-2D FS [7]. The aim of this paper is to argue that, at variance with the above theoretical statements, a FISDW state can be observed in a q-2D semi metal, namely, (TMTSF) 2 NO 3 under pressure.Among the members of the Bechgaard salts family, (TMTSF) 2 NO 3 exhibits numerous peculiar features. As the temperature decreases, an anion ordering (AO) transition with wave vector (1/2, 0, 0) is observed at ambient pressure at a temperature T AO ≃ 45 K [8,9] which remains independent of the magnetic field up to at least 36 T [10]. This leads to a q-2D FS with compensated electron and hole tubes [11]. At lower temperature, a SDW state with incommensurate wave vector and imperfect nesting is stabilized (T SDW = 9.1 K at ambient pressure) [12]. Under pressure higher than ∼ 8 kbar, the AO transition is shifted towards slightly higher temperatures [13] and a metallic state is stabilized at low temperature. Asymmetrical warping of the FS along the less conducting direction c* has been inferred from the absence of Yamaji features in the angular dependence of the magnetoresistance both in the SDW [14] and metallic [15] ...

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The electrochemical combination of the paramagnetic anion [Cr(NCS) 6 ] 3with the organic p-donors bis(ethylenedithio)tetrathiafulvalene (ET) and 4,5-bis(2-hydroxyethylthio)-4',5'-ethylenedithiotetrathiafulvalene (DHET-EDTTTF) leads to two new radical cation salts, namely (ET) 4 [Cr(NCS) 6 ]•PhCN (1) and (DHET-EDTTTF) 2 (NEt 4 )[Cr(NCS) 6 ] (2). Both have been characterized by X-ray crystallography, magnetic and resistivity measurements. The structure of 1 consists of alternating inorganic layers generated by the anions and organic layers in which the PhCN molecules are inserted; the organic sub-lattice is built up from four different ET units, three of them with a charge distribution of +1, the fourth being neutral. The organic sub-lattice of 2 contains a centrosymmetric [(DHET-EDTTTF • ) 2 ] 2+ dimer, in which the overlap mode is of the eclipsed type. Conductivity measurements indicate that compounds 1 and 2 are semiconductors with room temperature conductivities of 1.4 × 10 -2 and 6.1 × 10 -5 S cm -1 and activation energies of 0.24 and 0.23 eV, in 1 and 2, respectively. For both salts, magnetic measurements indicate (i) that the organic and inorganic parts are magnetically independent, and (ii) that the organic units are antiferromagnetically coupled. To cite this article: F.

Four conjugated polymers (P1-P4) consisting of alternating anthracene-9,10-diyl and 1,4-phenylene building blocks connected via ethynylene as well as vinylene (P1 and P2), ethynylene-only (P3), and vinylene-only (P4) moieties, respectively, were synthesized and studied. The phenylene units in all four polymers bear 2-ethylhexyloxy side-chains to promote good solubility. The three polymers with vinylene units (P1, P2, and P4) were prepared using the Horner-Wadsworth-Emmons reaction. For the synthesis of the aryleneethynylene polymer P3, the palladium-catalyzed Sonogashira cross-coupling reaction was used. The polymers were characterized by NMR, Fourier transform infrared spectroscopy, and Raman spectroscopy. Photophysical, absorption and photoluminescence, and electrochemical properties were studied. Spectroscopic ellipsometry measurements were performed to gain more insight on the optical properties. In addition, the transport properties were investigated using admittance spectroscopy. The bulk hole mobility and its dependence on the electric field were evaluated for P1 and P2.