https://doi.org/10.1140/epjb/e2005-00223-3
Anisotropy and field-dependence of the spin-density-wave dynamics in the
quasi one-dimensional conductor (TMTSF)
PF
1
1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring
57, 70550 Stuttgart, Germany
2
Institut za fiziku, P.O. Box 304,
HR-10001 Zagreb, Croatia
Corresponding author: a dressel@pil.physik.uni-stuttgart.de
Received:
3
December
2004
Revised:
14
February
2005
Published online:
19
July
2005
The anisotropic and non-linear transport properties of the
quasi one-dimensional organic conductor (TMTSF)2PF6 have been studied by dc,
radiofrequency, and microwave methods. Microwave experiments along all
three axes reveal that collective transport, which is considered to be
the fingerprint of the spin-density-wave condensate, also occurs in the
perpendicular 
direction. The pinned mode resonance is
present in the a and -axes response, but not along the
least conducting c* direction. The ac-field threshold, above which
the spin-density-wave response is non-linear, strongly decreases as the
temperature drops below 4 K. With increasing strength of the microwave
electric field and of the radiofrequency signal, the pinned mode and
the screened phason loss-peak shift to lower frequencies. In the
non-linear regime, in addition to the phason relaxation mode with
Arrhenius-like resistive decay, an additional mode with very long and
temperature-independent relaxation time appears below 4 K. We attribute
the new process to short-wavelength excitations
associated with discommensurations of the spin density wave close to commensurability.
PACS: 72.15.Nj – Collective modes (e.g., in one-dimensional conductors) / 75.30.Fv – Spin-density waves / 74.70.Kn – Organic superconductors
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005
