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@INPROCEEDINGS{Faley:1040661,
      author       = {Faley, Michael and Thomsen, Joachim and Lu, Penghan and
                      Vas, Joseph Vimal and Tavabi, Amir Hossein and
                      Dunin-Borkowski, Rafal},
      title        = {{S}uperconducting nanostructures and 2{D} superconducting
                      materials for operation in transmission electron
                      microscopes},
      reportid     = {FZJ-2025-01992},
      year         = {2025},
      abstract     = {Transmission electron microscopy enables high-resolution
                      imaging and spectroscopy on active quantum devices. Here, we
                      develop new technologies for operation of low-Tc and high-Tc
                      superconducting nanostructures inside transmission electron
                      microscope (TEM) in order to study their functionality down
                      to atomic level and temperatures down to 5 K. As thin-film
                      materials for the nanobridges, metals Ti and Nb were
                      combined into 3-layer heterostructures for adjusting
                      superconducting parameters of the nanobridge Josephson
                      junctions (nJJs) through the proximity effect. This allowed
                      to reduce spread of parameters (Tc, Ic, etc.) in ultrathin
                      superconducting films and to adjust operating temperature of
                      nJJs to the most stable operating temperature of the
                      commercial TEM sample holders cooled using liquid helium.
                      Cross-sectional TEM images of the Ti-Nb-Ti thin-film
                      heterostructure were obtained and revealed epitaxial growth.
                      Electron beam lithography and high selectivity reactive ion
                      etching with pure SF6 gas were used to pattern nJJs with
                      down to 10 nm width that is comparable to coherence length
                      in thin films of Nb. Nanoscale superconducting quantum
                      interference devices (nanoSQUIDs) with nJJs were prepared on
                      home-made SiN membrane and observed with TEM (Fig. 1a).
                      NanoSQUIDs were also prepared at a distance of below 200 nm
                      from the tip of a cantilever by using a focused ion beam to
                      achieve bulk nanosculpturing of the substrate. Measurements
                      revealed non-hysteretic I(V) characteristics of the nJJs and
                      nanoSQUIDs at operation temperature 5 K. 100-nm-thick NbSe2
                      flakes were transferred onto SiN membrane with Au contact
                      leads and a hole (Fig. 1b) and measured in TEM down to the
                      temperature below its Tc =7 K. High-Tc nanoSQUIDs were
                      realized with step-edge Josephson junctions. To realize
                      hybrid superconductor-ferromagnetic nanostructures for
                      further experiments in TEM, Permalloy nanodisks and
                      triangles with dimensions down to ~100 nm were prepared on
                      similar SiN membranes and studied by Lorentz microscopy and
                      electron holography methods. These technologies are
                      promising for the fabrication of superconducting electronics
                      for operation inside a TEM.},
      month         = {Feb},
      date          = {2025-02-19},
      organization  = {Conference on Superconductivity and
                       Functional Oxides, L'Aquila (Italy), 19
                       Feb 2025 - 21 Feb 2025},
      subtyp        = {After Call},
      cin          = {ER-C-1},
      cid          = {I:(DE-Juel1)ER-C-1-20170209},
      pnm          = {5351 - Platform for Correlative, In Situ and Operando
                      Characterization (POF4-535)},
      pid          = {G:(DE-HGF)POF4-5351},
      typ          = {PUB:(DE-HGF)6},
      url          = {https://juser.fz-juelich.de/record/1040661},
}