Ordered Bose Glass of Vortices in Superconducting YBa₂Cu₃O_{7−<i>δ</i>} Thin Films with a Periodic Pin Lattice Created by Focused Helium Ion Irradiation

Abstract

The defect-rich morphology of YBa2Cu3O7−δ (YBCO) thin films leads to a glass-like arrangement of Abrikosov vortices which causes the resistance to disappear in vanishing current densities. This vortex glass consists of entangled vortex lines and is identified by a characteristic scaling of the voltage–current isotherms. Randomly distributed columnar defects stratify the vortex lines and lead to a Bose glass. Here, we report on the observation of an ordered Bose glass in a YBCO thin film with a hexagonal array of columnar defects with 30 nm spacings. The periodic pinning landscape was engineered by a focused beam of 30 keV He+ ions in a helium-ion microscope.

Keywords

• copper-oxide superconductors
• vortex glass
• <i>ordered Bose glass</i>
• vortex matching
• voltage–current isotherms
• helium-ion microscope