Large critical current density Josephson <i>π</i> -junctions with PdNi barriers
We report large π-state critical current densities, Jc(π), in Nb/Pd89Ni11/Nb Josephson junctions at Pd89Ni11 thicknesses near the first π-state. We observe oscillations in the critical current with ferromagnetic barrier thickness consistent with a 0–π transition. For a junction with a 9.4 nm Pd89Ni11 barrier, we obtain Jc(π)=410 kA/cm2 at 4.2 K, exceeding values reported in prior PdNi-based studies. Magnetization measurements on continuous films, together with coercivity tests on patterned arrays, confirm that Pd89Ni11 exhibits perpendicular magnetic anisotropy, enabling zero-field operation without magnetic initialization. The combination of large Jc(π) and intrinsic anisotropy establishes Pd89Ni11 as a promising barrier material for passive π-shifters in superconducting digital logic and qubit architectures.
Authors
- Arjun Sapkota (ORCID: https://orcid.org/0000-0003-4182-8974)
- Robert M. Klaes (ORCID: https://orcid.org/0000-0002-1152-848X)
- Norman O. Birge (ORCID: https://orcid.org/0000-0001-7840-3908)
- Nathan Satchell (ORCID: https://orcid.org/0000-0003-1597-2489)
- R. Loloee
Institutions
- Texas State University (US)
- Michigan State University (US)
Publication Details
- Journal
- Applied Physics Letters
- Published
- 2026-03-09
- DOI
- https://doi.org/10.1063/5.0317028
- Primary Topic
- Physics of Superconductivity and Magnetism
- Type
- article
- Field-Weighted Citation Impact
- 0.00