J. Phys. IV France
Volume 131, December 2005
Page(s) 111 - 114
Publié en ligne 18 janvier 2006
International Workshop on Electronic Crystals
S. Brazovskii, P. Monceau and N. Kirova
J. Phys. IV France 131 (2005) 111-114

DOI: 10.1051/jp4:2005131024

Depinning of the Spin-Density Wave in (TMTTF)2Br under pressure

K. Nomura1, K. Ishimura1, K. Fujimoto1, N. Matsunaga1, T. Nakamura2, T. Takahashi3 and G. Saito4

1  Division of Physics, Hokkaido University, Sapporo, Japan
2  Institute for Molecular Science, Okazaki, Japan
3  Department of Physics, Gakushuin University, Tokyo, Japan
4  Division of Chemistry, Kyoto University, Kyoto, Japan

We have investigated the sliding motion of the SDW in the organic compound (TMTTF)2Br under the pressure with the measurement of the non-linear conductivity. Below the SDW transition temperature $T_{\rm SDW}$, we observed the sharp increase of conductivity with the clear threshold electric field $E_{\rm T}$, associated with the depinning of the SDW. For the typical sample, the temperature dependence of $E_{\rm T}$ shows a peak around 0.3 $T_{\rm SDW}$ in each pressure. In addition, the field hysteresis with the switching appears in the dc I-V characteristics around 0.3 $T_{\rm SDW}$. The excess conductivity, dominated by the kinetic friction, shows a sharp increase below 0.3 $T_{\rm SDW}$. These behaviors indicate that the sliding mechanism of SDW varies across 0.3 $T_{\rm SDW}$, which is almost equal to the sub-phase transition temperature. This fact suggests that the transition at 0.3 $T_{\rm SDW}$ is associated with both the magnetic and charge degrees of freedom.

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