Superconductivity in amorphous and crystalline Re-Lu films

Serafim Teknowijoyo; Armen Gulian

doi:10.1088/1361-6668/ad1f7e

paper

Superconductivity in amorphous and crystalline Re-Lu films

arXiv:2307.16313 · doi:10.1088/1361-6668/ad1f7e

Abstract

We report on magnetron deposition and superconducting properties of a novel superconducting material: rhenium-lutetium films on sapphire substrates. Different compositions of Re $_{x}$ Lu binary are explored from $x \approx 3.8$ to close to pure Re stoichiometry. The highest critical temperature, up to $T_{c} \approx$ 6.95 K, is obtained for $x \approx 10.5$ . Depending on the deposition conditions, polycrystalline or amorphous films are obtainable, both of which are interesting for practice. Crystalline structure of polycrystalline phase is identified using grazing incidence X-ray diffractometry as a non-centrosymmetric superconductor. Superconducting properties were characterized both resistively and magnetically. Demonstration of superconductivity in this material justifies the point of view that Lu plays a role of group 3 transition metal in period 6 of the Periodic table of elements. In analogy with Re $_{0.82}$ Nb $_{0.18}$ , Re $_{6}$ Ti, Re $_{6}$ Hf and Re $_{6}$ Zr, one can expect that crystalline Re--Lu is also breaking the time-reversal symmetry (this still waits confirmation). Magnetoresistivity and AC/DC susceptibility measurements allowed us to determine H $_{c 1}$ and H $_{c 2}$ of these films, as well as estimate coherence length $ξ (0)$ and magnetic penetration depth $λ_{L} (0)$ . We also provide information on surface morphology of these films.

Superconductivity in amorphous and crystalline Re-Lu films

Abstract

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