Homogeneous superconducting state at 8.1 K under ambient pressure in the organic conductor β-(BEDT-TTF)2I3

We report the observation of the first narrow and complete superconducting transition yet obtained in β-(BEDT-TTF)2I3 at 8.1 K and ambient pressure after pressurization up to 1.5 kbar and a release of the helium gas pressure at low temperature. We show experimental evidences indicating that the metastable state giving rise to homogeneous superconductivity at ambient pressure is not stable above 250 K

Two superconducting phases in the organic conductor: β-(BEDT-TTF)2I3

We have investigated the nature and the stability of the high-Tc(∼8 K) and low-Tc (∼1.5 K)superconducting phases (respectively called β-H and β-L) of the organic conductor β-(BEDT-TTF)2I3. First, by resistivity measurements and following a well-defined temperature-pressure cycling process, we show that the β-H phase is stabilized at ambient pressure and low temperature, exhibiting a very sharp and complete superconducting transition at 8.1 K and 1 bar. Secondly, an AC-susceptibility study reveals that this state is stable and exhibits bulk superconductivity at high Tc and ambient P as long as the sample is not warmed above 125 K. Finally, we present NMR results on the 1H spin-lattice relaxation rate behaviour in both the β-H phase and the β-L phase

Main properties and current applications of some polysaccharides as biomaterials

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