Signatures of superconducting triplet pairing in Ni--Ga-bilayer junctions
arXiv:2102.03083 · doi:10.1088/1367-2630/ac5bbb
Abstract
Ni-Ga bilayers are a versatile platform for exploring the competition between strongly antagonistic ferromagnetic and superconducting phases. We characterize the impact of this competition on the transport properties of highly-ballistic Al/Al2O3(/EuS)/Ni-Ga tunnel junctions from both experimental and theoretical points of view. While the conductance spectra of junctions comprising Ni (3 nm)-Ga (60 nm) bilayers can be well understood within the framework of earlier results, which associate the emerging main conductance maxima with the junction films' superconducting gaps, thinner Ni (1.6 nm)-Ga (30 nm) bilayers entail completely different physics, and give rise to novel large-bias (when compared to the superconducting gap of the thin Al film as a reference) conductance-peak subseries that we term conductance shoulders. These conductance shoulders might attract considerable attention also in similar magnetic superconducting bilayer junctions, as we predict them to offer an experimentally well-accessible transport signature of superconducting triplet pairings that are induced around the interface of the Ni-Ga bilayer. We further substantiate this claim performing complementary polarized neutron reflectometry measurements on the bilayers, from which we deduce (1) a nonuniform magnetization structure in Ga in a several nanometer-thick area around the Ni-Ga boundary and can simultaneously (2) satisfactorily fit the obtained data only considering the paramagnetic Meissner response scenario. While the latter provides independent experimental evidence of induced triplet superconductivity inside the Ni-Ga bilayer, the former might serve as the first experimental hint of its potential microscopic physical origin.
24 pages, 10 figures, 1 table
References in corpus (15)
- Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
- A spin triplet supercurrent through the half-metallic ferromagnet CrO2
- Signature of magnetic-dependent gapless odd frequency states at superconductor/ferromagnet interfaces
- Spin-dependent Cooper Pair Phase and Pure Spin Supercurrents in Strongly Polarized Ferromagnets
- Manifestation of the odd-frequency spin-triplet pairing state in diffusive ferromagnet / superconductor junctions
- Reversible control of spin-polarised supercurrents in ferromagnetic Josephson junctions
- Pairing symmetry conversion by spin-active interfaces in superconducting junctions
- Majorana Fermions in Chiral Topological Ferromagnetic Nanowires
- Revealing the magnetic proximity effect in EuS/Al bilayers through superconducting tunneling spectroscopy
- Magnetoanisotropic Josephson effect due to interfacial spin-orbit fields in superconductor/ferromagnet/superconductor junctions
- Supercurrent in ferromagnetic Josephson junctions with heavy metal interlayers. II. Canted magnetization
- Consequences of bulk odd-frequency superconducting states for the classification of Cooper pairs
- Superconducting triplet pairings and anisotropic magnetoresistance effects in ferromagnet/superconductor/ferromagnet double-barrier junctions
- Electrical manipulation of Majorana fermions in an interdigitated superconductor-ferromagnet device
- Supergap and subgap enhanced currents in asymmetric {S_1FS_2} Josephson junctions