skip to main content


Title: Superconductivity of Electrodeposited Sn Films
Tin (Sn) films are electrodeposited on Au seed layers for the investigation of superconductivity. The effects of the presence of suppressing additives in electrolyte, the thickness of Sn films, and the room temperature aging of deposited Sn films on the superconducting transition behavior are systematically studied. In addition, the crystallographic structure of electrodeposited Sn and its evolution along with aging time are characterized and are discussed in conjunction with the superconductivity behavior. The current work represents an important step towards the processing of technologically viable superconducting devices.  more » « less
Award ID(s):
1941820 2016541
NSF-PAR ID:
10424838
Author(s) / Creator(s):
Date Published:
Journal Name:
Journal of The Electrochemical Society
Volume:
170
Issue:
3
ISSN:
0013-4651
Page Range / eLocation ID:
032506
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. The nature of superconductivity in SrTiO 3 , the first oxide superconductor to be discovered, remains a subject of intense debate several decades after its discovery. SrTiO 3 is also an incipient ferroelectric, and several recent theoretical studies have suggested that the two properties may be linked. To investigate whether such a connection exists, we grew strained, epitaxial SrTiO 3 films, which are known to undergo a ferroelectric transition. We show that, for a range of carrier densities, the superconducting transition temperature is enhanced by up to a factor of two compared to unstrained films grown under the same conditions. Moreover, for these films, superconductivity emerges from a resistive state. We discuss the localization behavior in the context of proximity to ferroelectricity. The results point to new opportunities to enhance superconducting transition temperatures in oxide materials. 
    more » « less
  2. Abstract

    Nb3Sn is a promising next-generation material for superconducting radiofrequency cavities, with significant potential for both large scale and compact accelerator applications. However, so far, Nb3Sn cavities have been limited to continuous wave accelerating fields <18 MV m−1. In this paper, new results are presented with significantly higher fields, as high as 24 MV m−1in single cell cavities. Results are also presented from the first ever Nb3Sn-coated 1.3 GHz 9-cell cavity, a full-scale demonstration on the cavity type used in production for the European XFEL and LCLS-II. Results are presented together with heat dissipation curves to emphasize the potential for industrial accelerator applications using cryocooler-based cooling systems. The cavities studied have an atypical shiny visual appearance, and microscopy studies of witness samples reveal significantly reduced surface roughness and smaller film thickness compared to typical Nb3Sn films for superconducting cavities. Possible mechanisms for increased maximum field are discussed as well as implications for physics of RF superconductivity in the low coherence length regime. Outlook for continued development is presented.

     
    more » « less
  3. Abstract We report the superconductivity of the topological nodal-line semimetal candidate Sn x NbSe 2- δ with a noncentrosymmetric crystal structure. The superconducting transition temperature T c of Sn x NbSe 2- δ drastically varies with the Sn concentration x and the Se deficiency δ , and reaches 12 K, relatively higher than those of known topological superconductors. The upper critical field of this compound shows unusual temperature dependence, inconsistent with the WHH theory for conventional type-II superconductors. In a low-T c sample, the zero-temperature limit of the upper critical field parallel to the ab plane exceeds the Pauli paramagnetic limit estimated from the simple BCS weak coupling model by a factor of ∼ 2, suggestive of unusual superconductivity stabilized in Sn x NbSe 2- δ . Together with the robust superconductivity against disorder, these observations indicate that Sn x NbSe 2- δ is a promising candidate to explore topological superconductivity. 
    more » « less
  4. Improving materials used to make qubits is crucial to further progress in quantum information processing. Of particular interest are semiconductor-superconductor heterostructures that are expected to form the basis of topological quantum computing. We grew semiconductor indium antimonide nanowires that were coated with shells of tin of uniform thickness. No interdiffusion was observed at the interface between Sn and InSb. Tunnel junctions were prepared by in situ shadowing. Despite the lack of lattice matching between Sn and InSb, a 15-nanometer-thick shell of tin was found to induce a hard superconducting gap, with superconductivity persisting in magnetic field up to 4 teslas. A small island of Sn-InSb exhibits the two-electron charging effect. These findings suggest a less restrictive approach to fabricating superconducting and topological quantum circuits.

     
    more » « less
  5. The unconventional superconductivity in Sr 2 RuO 4 is infamously susceptible to suppression by small levels of disorder such that it has been most commonly studied in extremely high-purity bulk crystals. Here, we harness local structural and spectroscopic scanning transmission electron microscopy measurements in epitaxial thin films of Sr 2 RuO 4 to disentangle the impact of different types of crystalline disorder on superconductivity. We find that cation off-stoichiometry during growth gives rise to two distinct types of disorder: mixed-phase structural inclusions that accommodate excess ruthenium and ruthenium vacancies when the growth is ruthenium-deficient. Several superconducting films host mixed-phase intergrowths, suggesting this microstructural disorder has relatively little impact on superconductivity. In a non-superconducting film, on the other hand, we measure a high density of ruthenium-vacancies [Formula: see text] with no significant reduction in the crystallinity of the film. The results suggest that ruthenium vacancy disorder, which is hidden to many structural probes, plays an important role in suppressing superconductivity. We discuss the broader implications of our findings to guide the future synthesis of this and other layered systems. 
    more » « less