2023/04/05 by M. Karrer, K. Wurster, Karrer, M. +11 · 2 citations
Engineering · Materials Science · Physics and Astronomy · #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Semiconductor materials and devices #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.2304.02749
openalex publication_date 2023/04/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Using a 30 keV focused He ion beam (He-FIB) with a wide range of irradiation doses D=100 to 1000 ions/nm we fabricated Josephson and resistive barriers within microbridges of epitaxially grown single crystalline YBCO thin films and investigated the change of their electric transport properties with time. One set of samples (#1A) was simply stored at room temperature under nitrogen atmosphere. A second set (#2D) was post-annealed at 90^∘ C using high oxygen pressures and a third set (#2E) at low oxygen pressures. We found that for #1A the critical current density jc at 4.2 K changes as jc∝exp(-√(t/τ)) with time t, where the relaxation times τ increases exponentially with D, which can be described within a limited diffusion based model. In order to increase the diffusion rate we annealed the junctions from #2D at 90^∘ C for 30 min in oxygen environment. Directly after annealing the critical current density jc increased, while the normal state resistance Rn decreased. Repeated measurements showed that within a week the junctions relaxed to a quasi-stable state, in which the time scale for junction parameter variations increased to several weeks, making this a feasible option to achieve temporal stability of parameters of He-FIB Josephson junctions in YBCO.