In-situ pulsed laser deposited superconducting Cu xMo 6S 8 (2 ≤ x ≤ 4) thin films epitaxially grown on R-plane Al 2O 3
Thin films of Chevrel phases Cu xMo 6S 8 (2 ≤ x ≤ 4) have been in-situ deposited by laser ablation. Epitaxial growth of these films have been achieved on suitable substrates. Cu xMo 6S 8 epitaxial layers have been grown on R-cut Al 2O 3 single-crystal substrates (corresponding to the (1 overline1 0 2) Hex or (1 1 0) R orientation in the hexagonal or rhombohedral indexing, respectively) and present a (1 0 0) R preferential orientation as evidenced by X-ray diffraction in different modes (i.e. θ-2 θ, φ-scans). The film composition has been checked by Rutherford backscattering spectrometry. The superconducting transition temperature has been determined from d.c. resistive measurements and a.c. susceptibility measurements. The critical temperature Tc ( R = 0) is typically between 9.5 and 10.3 K for x ∼ 2 and decreases when x increases, in good agreement with the bulk materials behaviour. Moreover the superconducting transition is narrow, the full width at half maximum of the in quadrature inductive signal, χ″, ranging between 0.1 and 0.5 K.