Impurity effect on the in-plane penetration depth of the organic superconductors κ-(BEDT-TTF) 2X (X = Cu(NCS) 2 and Cu[N(CN) 2]Br)

Naoki Yoneyama, Akihiro Higashihara, Takahiko Sasaki, Tsutomu Nojima, Norio Kobayashi

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22 Citations (Scopus)

Abstract

We report the in-plane penetration depth λ of single crystals κ-(BEDT-TTF) 2X (X = Cu(NCS) 2 and Cu[N(CN) 2]Br) by means of the reversible magnetization measurements under the control of cooling-rate. In X = Cu(NCS) 2, λ (0) obtained by an extrapolation toward T = 0 K does not change by cooling-rate within the experimental accuracy, while T c is slightly reduced. On the other hand, in X = Cu[N(CN) 2]Br, λ (0) indicates a distinct increase by cooling faster. The different behavior of λ (0) on cooling-rate between the two salts is quantitatively explained in terms of the local-clean approximation (the London model), considering that the former salt belongs to the very clean system and the latter the moderate clean one. The good agreement with this model demonstrates that disorders of the ethylene-group in BEDT-TTF introduced by cooling faster increase the electron(quasiparticle)-scattering, resulting in shorter mean free path.

Original languageEnglish
Pages (from-to)1290-1296
Number of pages7
Journaljournal of the physical society of japan
Volume73
Issue number5
DOIs
Publication statusPublished - 2004 May

Keywords

  • Cooling rate
  • Disorder
  • Ethylene group
  • Mean free path
  • Organic superconductor
  • Penetration depth

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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