SKM 2021 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 1: Focus Session: Disordered and Granular Superconductors: Fundamentals and Applications in Quantum Technology I
TT 1.3: Talk
Monday, September 27, 2021, 10:45–11:00, H6
Nanocrystalline boron-doped diamond as a model granular superconductor — •Georgina Klemencic1, David Perkins2, Jon Fellows3, Soumen Mandal1, Chris Muirhead2, Robert Smith2, Sean Giblin1, and Oliver Williams1 — 1Cardiff University, UK — 2University of Birmingham, UK — 3University of Bristol, UK
We present results of an experimental investigation into Boron-doped Nanocrystalline Diamond (BNCD), which we argue to be an exemplary model for granularity in a low-temperature superconducting system.
Through measurement of the fluctuation conductivity [1], we have indirectly measured the inter- and intragrain diffusion lengths, in an experimental application of the theoretically proposed ‘fluctuation spectroscopy’ technique. The fluctuation conductivity is well predicted by theories of granular superconductors and the magnetoresistance exhibits the same glassy behaviour as high-Tc samples [2]. In this respect, we find that BNCD is a good system for distinguishing high-Tc behaviours from granular superconductor behaviours.
A special feature of BNCD is its morphology, in which grains extend vertically through the film, making the bulk material structurally akin to a naturally occurring Josephson junction array. In recent work, we have found evidence of metastable phase slip-like excitations in the current-voltage characteristics of macroscopic bridges fabricated from BNCD, which we attribute to this morphology [3].
[1] G. M. Klemencic et al., Phys. Rev. Mater. 1.4 (2017): 044801
[2] G. M. Klemencic et al., Sci. Rep. 9.1 (2019): 1-6
[3] G. M. Klemencic et al., Carbon 175 (2021): 43-49