F. Goze

Transport properties and giant Shubnikov-de Haas oscillations in the first organic conductor with metal complex anion containing selenocyanate ligand, (ET)2 T1Hg(SeCN)4

Abstract Temperature dependence of the resistivity in various crystallographic directions and high pulsed field magnetoresistance of organic metal α-(ET) 2 TlHg(SeCN) 4 have been studied at temperatures down to 80 mK. Giant Shubnikov-de Haas oscillations, which are attributed to the two-dimensional nature of the cylindrical Fermi surface with a very small warping along the direction of the lowest conductivity have been observed. Four harmonics of the fast oscillations with fundamental frequency F 0 = 653 ± 3 T and slow frequency oscillations with F s = 38 ± 5 T have been revealed.

Angular and magnetic field dependencies of the magnetoresistance of λ-(BETS)2FeCl4 in the field-restored high conductivity state

Abstract The very sharp metal-insulator transition, which occurs at 8 K at ambient pressure in λ-(BETS) 2 FeCl 4 is suppressed when applying magnetic fields >10T. This unusual phenomenon may be connected to ferromagnetic ordering of the Fe 3+ moments, which could drive some “evaporation” of the previously condensed conduction electrons, into a field-restored highly conducting state (FRHCS) in which oscillations of the magnetoresistance are reported.

Slow and Fast Quantum Oscillations in the High-Field Magnetoresistance of (TMTSF)2NO3: Magnetic Breakthrough Linked to SDW Gap Opening

We report a study of the transverse magnetoresistance in the spin-density-wave state of the organic conductor (TMTSF)2NO3 at ambient pressure, in fields up to 37 T. For field along the lowest conductivity axis (c*), two series of quantum oscillations, with temperature-independent frequencies of 63 T and 248 T, respectively, are observed in the 2-12 K temperature range. The oscillation amplitude of both series decreases when the temperature departs from 4.2 K. This is tentatively interpreted within the framework of magnetic breakthrough and quantum interferences.

Magnetoresistance in pulsed fields, band structure calculations and charge-density wave instability in (TSeT)/sub 2/C1

Abstract Diffuse X-rays measurements assign the 26 K metal-semimetal transition in (TSeT) 2 Cl, where TSeT = tetraselenotetracene, to the stabilization of a 2k F =c∗/4 charge-density wave ground state. Tight-binding extended Huckel band calculations suggest that 2k F yields to a partial nesting of the four conduction bands. Transverse magnetoresistance experiments performed up to 37 T confirm the previous observation of SdH oscillations. The 0 + Landau level is evidenced for the first time.

Effect of the cooling rate on the transverse magnetoresistance of (TSeT)2Cl in its charge-density wave ground state

Abstract Transverse magnetoresistance measurements were performed in pulsed magnetic fields up to 37 T in the metallic state and the semimetallic charge-density wave ground state of (TSeT) 2 Cl. Cooling with two different rates from 30 K down to 4.2 K yields two Shubnikov-de Haas oscillation frequencies. The 0 + Landau level is evidenced for both oscillation series.

High field magnetoresistance of (TMTSF)2NO3: phase transitions and quantum oscillations

Abstract Transverse magnetoresistance of the organic conductor (TMTSF) 2 NO 3 has been measured at ambient pressure, in fields up to 37T and in the temperature range 2–77K. For field along the lowest conductivity axis (c∗), the magnetic field is found to increase the SDW transition temperature, in agreement with theoretical predictions for SDW phase with imperfect nesting. On the other hand, two series of quantum oscillations, with frequency of 63T and 246T respectively, are observed in the 2–10K range. Both series are connected to the SDW transition but cannot be accounted for by Shubnikov-de Haas model. Anisotropy of these oscillations is studied at 4.2K.

High field magnetoresistance of (TMTSF)/sub 2/NO/sub 3/: phase transmons and quantum oscillations

Summary form only given. We report a study of the transverse magnetoresistance of the organic conductor (TMTSF)/sub 2/NO/sub 3/ at ambient pressure, in fields up to 37T and in the temperature range from 2 to 77K. For field along the lowest conductivity axis (c/sup */), two series of quantum oscillations, with temperature independent frequencies of 63T and 247T respectively, are observed in the 2-10K temperature range. The oscillations amplitude of both series decreases when the temperature departs from nearby 4K. Both series are connected to the SDW transition but cannot be accounted for by SdH model. The data is tentatively interpreted, in this temperature range, within the framework of magnetic breakthrough and quantum interferences. The anisotropy of these oscillations is also studied at 4.2K. On the other hand, the magnetic field is found to increase the SDW transition temperature, in agreement with theoretical predictions for SDW phase with imperfect nesting.