https://doi.org/10.1007/s100510050647
Low temperature thermodynamical properties of the organic chain conductor (TMTSF)2AsF6
1
Centre de Recherches sur les Très Basses
Températures (Associé à l'Université Joseph Fourier,
CNRS.) , B.P. 166, 38042 Grenoble Cedex 9, France
2
Institute of Physics, POB 304, HR 10001 Zagreb, Croatia
3
Department of Material Science, Faculty of Science,
Himeji Institute of Technology,
Kamigohri, Hyogo 678-12, Japan
Received:
17
March
1998
Revised:
27
July
1998
Accepted:
22
September
1998
Published online: 15 February 1999
We report on specific heat measurements of the quasi-one-dimensional organic salt (TMTSF)2AsF6 in its spin density wave state between 75 mK and 7 K. Similarly to (TMTSF)2PF6, we find discontinuities in the lattice contribution at 1.9 K an d 3.5 K ascribed to sub-spin density wave phases. Time-dependent effects due to dynamics of low-energy excitations in metastable states occur only below 0.2 K which yields an activation energy for the equilibrium energy relaxation process of 0.34 K, 4-5 times smaller than found for (TMTSF)2PF6. Finally the reduction of the low-energy excitations contribution to the specific heat in comparison to PF6 reveals an intermediate cubic-like regime between 0.25 and 0.5 K that we tentatively describe as the phason contribution of the incommensurate spin density wave modulation.
PACS: 75.30.Fv – Spin density wave / 05.70.Ln – Non-equilibrium thermodynamics, irreversible processes
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999