J. Phys. IV France 114 (2004) 107
DOI: 10.1051/jp4:2004114021

Non magnetic anion substitution in (TMTSF) ₂ClO ₄: Consequences on the superconductivity

N. Joo^{1, 2}, C. Pasquier¹, P. Auban Senzier¹, D. Jérome¹ and K. Bechgaard<sup>3

1</sup>  Laboratoire de Physique des Solides, Bât. 510, Université Paris-Sud, 91405 Orsay, France
    e-mail: joo@lps.u-psud.fr
²  Faculté des Sciences de Tunis, LPMC, Campus Universitaire, 1060 Tunis, Tunisie
³  Department of Solid State Physics, Risø National Laboratory, 4000 Roskilde, Denmark

Abstract
Non magnetic impurities substitution is a method to check the microscopic origin of superconductivity. In (TMTSF) ₂ClO ₄, we substitute a small fraction of the ClO ₄ anions by ReO ₄. The anion ordering temperature is shown to be unaffected by alloying in the explored range 0-3.1%. However, the critical temperature is strongly reduced with increased residual resistivity obtained through alloying and/or increased speed of cooling. Our results are compatible with an unconventional superconductivity in the Bechgaard salts. Key words. Bechgaard salts - unconventional superconductivity - alloys.

© EDP Sciences 2004