arXiv subjects

S. Gueron

Publications and source records attributed to S. Gueron.

20 records · Page 2Linked to original sources

arXiv2001

Superconductivity in Ropes of Single-Walled Carbon Nanotubes

We report measurements on ropes of Single Walled Carbon Nanotubes (SWNT) in low-resistance contact to non-superconducting (normal) metallic pads, at low voltage and at temperatures down to 70 mK. In one sample, we find a two order of magnitude resistance drop below 0.55 K, which is destroyed by a magnetic field of the order of 1T, or by a d.c. current greater than 2.5 microA. These features strongly suggest the existence of superconductivity in ropes of SWNT.

cond-mat.mes-hall↗

arXiv1999

Tunneling Via Individual Electronic States in Ferromagnetic Nanoparticles

We measure electron tunneling via discrete energy levels in ferromagnetic cobalt particles less than 4 nm in diameter, using non-magnetic electrodes. Due to magnetic anisotropy, the energy of each tunneling resonance shifts as an applied magnetic field rotates the particle's magnetic moment. We see both spin-increasing and decreasing tunneling transitions, but we do not observe the spin degeneracy at small magnetic fields seen previously in non-magnetic materials. The tunneling spectrum is denser than predicted for independent electrons, possibly due to spin-wave excitations.

cond-mat.mes-hall↗