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We report on magnetron deposition of thin superconducting rhenium films on sapphire substrates. During the deposition, substrates were held at ambient temperature. Critical temperature of the films is Tc ~ 3.6 K. Films have polycrystalline structure, and grazing incidence X-ray diffractometry indicates that crystalline lattice parameters are somewhat larger compared to the bulk ones. Magnetoresistive and AC/DC susceptibilities allowed us to determine Hc1 and Hc2 of these films, as well as estimate coherence length ξ(0) and magnetic penetration depth λL(0). We also provide information on surface morphology of these films. [ABSTRACT FROM AUTHOR]

A material called LK-99, a modified-lead apatite crystal structure with the composition Pb10 – xCux(PO4)6O (0.9 < x < 1.1) has been reported to be an above-room-temperature superconductor at ambient pressure. It is hard to expect that it will be straightforward for other groups to reproduce the original results. We provide here some remarks which may be helpful for a success. [ABSTRACT FROM AUTHOR]

The interplay between superconductivity and charge-density wave (CDW) in 2H-NbSe2 is not fully understood despite decades of study. Artificially introduced disorder can tip the delicate balance between two competing long-range orders, and reveal the underlying interactions that give rise to them. Here we introduce disorder by electron irradiation and measure in-plane resistivity, Hall resistivity, X-ray scattering, and London penetration depth. With increasing disorder, the superconducting transition temperature, Tc, varies non-monotonically, whereas the CDW transition temperature, TCDW, monotonically decreases and becomes unresolvable above a critical irradiation dose where Tc drops sharply. Our results imply that the CDW order initially competes with superconductivity, but eventually assists it. We argue that at the transition where the long-range CDW order disappears, the cooperation with superconductivity is dramatically suppressed. X-ray scattering and Hall resistivity measurements reveal that the short-range CDW survives above the transition. Superconductivity persists to much higher dose levels, consistent with fully gapped superconductivity and moderate interband pairing. [ABSTRACT FROM AUTHOR]