Influence of the Cooling Rate on the Superconducting Properties of the Organic Solid Di-Tetramethyltetraselenafulvalenium-Perchlorate,(TMTSF)2ClO4

Abstract

Specific-heat measurements on the organic solid di-tetramethyltetraselenafulvalenium-perchlorate ${\mathrm{}\left(\mathrm{TMTSF}\right)\mathrm{}}_2$ Cl${\mathrm{O}}_4$ demonstrate that $T_c$ decreases as much as 22%, when the cooling rate below 40 K is changed from 0.1 K/min (relaxed state) to 10 K/min (quenched state). The phenomenon is fully reversible as indicated by annealing experiments. The parameters of the superconducting state, the specific-heat jump, the entropy, and the upper critical fields ($\parallel c^{*}$) are strongly affected by the quenching process. A possible explanation is that quenching freezes out lattice disorder.