Fig. 10: | Nature Communications

Fig. 10

From: Discovery of superconductivity in quasicrystal

Fig. 10

Superconducting upper critical field. The superconducting upper critical fields \(H_{\tt c2}\) of the QC, the 2/1AC, the 1/1AC_F are plotted in the form of \(h = - H_{{\mathrm{c}}2}/(T_{\mathrm{c}}\mathrm{d}H_{{\mathrm{c}}2}/\mathrm{d}T|_{T = T_{\mathrm{c}}})\) vs \(t = T/T_{\mathrm{c}}\). The solid curve denotes the Werthamer–Helfand–Hohenberg theory in the dirty limit. The inset shows \(H_{{\mathrm{c}}2}(T)\) of the same samples as in the main frame. Note that the upper critical field in the limit of zero temperature of the 1/1AC_F (\(H_{\tt c2}(0) \cong 500\) Oe) substantially exceeds that of metal Al (\(\sim 100\) Oe), excluding the possibility that the superconductivity would arise from Al-derived impurity phase