Structural changes in YBa2Cu3O7 superconducting nanojunctions formed using focused He+ ion beam

We will study the changes in the crystal lattice of YBa2Cu3O7 caused by a focused He+ ion beam, which is a common tool for nanopatterning. In bulk, YBa2Cu3O7 under irradiation undergoes a superconductor-to-insulator transition, which is accompanied by the change of the crystal lattice from orthorhombic to tetragonal. However, in microscopic areas, the structural phase transition might be suppressed due to the impossibility of the crystal lattice to accommodate strong lattice distortions.
Using a focused He+ ion beam, we will irradiate small areas of a YBa2Cu3O7 film with different ion doses and cut out nanoparticles (NPs) containing the irradiated areas. We will employ the multi-Bragg peak CDI technique, measure the coherent scattered intensity around three YBCO Bragg peaks and reconstruct the strain tensor field in the NPs. This spatially resolved information will allow us to identify the structural changes and study the influence of ion dose and size of the irradiated area.