Impurity Effect on the In-plane Penetration Depth of the Organic Superconductors $\kappa$-(BEDT-TTF)${}_{2}X$ ($X$ = Cu(NCS)${}_2$ and Cu[N(CN)${}_2$]Br)

N. Yoneyama, A. Higashihara, T. Sasaki +2

We report the in-plane penetration depth ${\lambda }_{\parallel }$ of single crystals $\kappa$-(BEDT-TTF)${}_{2}X$ ($X=$ Cu(NCS)${}_2$ and Cu[N(CN)${}_2$]Br) by means of the reversible magnetization meas…