Mesoscale Fabrication of the Thin-filmed Strange Metal Sr₃Ru₂O₇

In the bulk,Sr₃Ru₂O₇(SRO327) exhibits a strange metal  phase in the presence of a field-tuned quantum critical point. One avenue of study of such non-Fermi liquids is electronic transport and spectroscopy at the mesoscopic scale ( i.e. shot noise and tunneling density of states measurements). However, these techniques require the fabrication of mesoscopic devices, typically based on thin films of the starting material. While recent progress has been made in the growth of SRO327 films, SRO327’s chemical and structural sensitivity bring in problems in the fabrication of the nanostructures required. Standard techniques like e-beam lithography (EBL) can damage the SRO327 films at the high column voltages, required for nanoscale resolution. Most etchants drastically damage and change the properties of SRO327 as well. We describe recent progress in the use of focused ion beam (FIB) patterning of this material, and transport properties of the resulting constrictions. Outlining the desired structure with a FIB allows one to achieve the nanoscale resolution to fabricate required nanostructures while avoiding heavy damage to the SRO327 films.