Electronic transport through ferromagnetic and superconducting junctions with spin-filter tunneling barriers

Abstract

We present a theoretical study of the quasiparticle and subgap conductance of generic $X/I_{sf}/S_M$ junction with a spin-filter barrier $I_{sf}$, where $X$ is either a normal $N$ or a ferromagnetic metal $F$ and $S_M$ is a superconductor with a built-in exchange field. Our study is based on the tunneling Hamiltonian and the Green's function technique. First, we focus on the quasiparticle transport, both above and below the superconducting critical temperature. We obtain a general expression for the tunneling conductance which are valid for arbitrary values of the exchange field and arbitrary magnetization directions in the electrodes and in the spin-filter barrier. In the second part we consider the subgap conductance of a normal metal-superconductor junction with a spin-filter barrier. We provide a heuristic derivation of new boundary conditions for the quasiclassical Green's functions which take into account the spin-filter effect at the interface. With the help of these boundary conditions, we show how the proximity effect and the subgap conductance is suppressed by spin-filtering in a $N/I_{sf}/S$ junction, where $N$ is a normal metal. Our work provides useful tools for the study of spin-polarized transport in hybrid structures both in the normal and the superconducting state.

9 pages; 4 figures, some minor typos are fixed

References in corpus (7)

• A spin triplet supercurrent through the half-metallic ferromagnet CrO2
• Half-integer Shapiro steps at the 0-pi crossover of a ferromagnetic Josephson junction
• Josephson tunnel junctions with strong ferromagnetic interlayer
• Pairing symmetry conversion by spin-active interfaces in superconducting junctions
• Theory of superconducting and magnetic proximity effect in S$\mid$F structures with inhomogeneous magnetization textures and spin-active interfaces
• Spin-polarized Josephson and quasiparticle currents in superconducting spin-filter tunnel junctions
• Josephson current in ballistic heterostructures with spin-active interfaces

Cited by in corpus (49)

• Colloquium: Nonequilibrium effects in superconductors with a spin-splitting field
• Huge thermoelectric effects in ferromagnet-superconductor junctions in the presence of a spin-splitting field
• Theory of the spin-galvanic effect and the anomalous phase-shift ${\phi }_0$ in superconductors and Josephson junctions with intrinsic spin-orbit coupling
• General Boundary Conditions for Quasiclassical Theory of Superconductivity in the Diffusive Limit: Application to Strongly Spin-polarized Systems
• Thermal, electric and spin transport in superconductor/ferromagnetic-insulator structures
• Pure 2nd harmonic current phase relation in Spin filter Josephson junctions
• Anomalous current in diffusive ferromagnetic Josephson junctions
• Giant thermoelectric effects in a proximity-coupled superconductor-ferromagnet device
• Triplet proximity effect in superconducting heterostructures with a half-metallic layer
• Very large thermophase in ferromagnetic Josephson junctions
• Long-range spin and charge accumulation in mesoscopic superconductors with Zeeman splitting
• Tuning of Magnetic Activity in Spin-Filter Josephson Junctions Towards Spin-Triplet Transport
• Triplet Cooper pairs induced in diffusive s-wave superconductors interfaced with strongly spin-polarized magnetic insulators or half-metallic ferromagnets
• Efficient electron refrigeration using superconductor/spin-filter devices
• Magnetoelectric effects in Josephson junctions
• Nematic versus ferromagnetic spin filtering of triplet Cooper pairs in superconducting spintronics
• Large enhancement of spin pumping due to the surface bound states in normal metal/superconductor structures
• Superconductivity near a magnetic domain wall
• Long-range spin imbalance in mesoscopic superconductors under a Zeeman splitting
• Voltage-induced thin-film superconductivity in high magnetic fields
• Injection of nonequilibrium quasiparticles into Zeeman-split superconductors: a way to create long-range spin imbalance
• Charge transport through spin-polarized tunnel junction between two spin-split superconductors
• Chirality selective spin interactions mediated by the superconducting current
• Dynamics of two ferromagnetic insulators coupled by superconducting spin current
• Phase-dependent heat transport through magnetic Josephson tunnel junctions
• Supercurrent Induced Charge-Spin Conversion in Spin-Split Superconductors
• The inverse proximity effect in strong ferromagnet-superconductor structures
• Quantum interference hybrid spin-current injector
• The quasiclassical theory for interfaces with spin--orbit coupling
• Current rectification in junctions with spin-split superconductors
• Spin Hanle effect in mesoscopic superconductors
• Stimulated quasiparticles in spin-split superconductors
• Spin currents driven by the Higgs mode in magnetic superconductors
• Manifestation of a spin-splitting field in a thermally-biased Josephson junction
• Quasiclassical boundary conditions for spin-orbit coupled interfaces with spin-charge conversion
• Quasiparticle density of states and triplet correlations in superconductor/ferromagnetic-insulator structures across a sharp domain wall
• ${\theta }_0$ thermal Josephson junction
• Signatures of superconducting triplet pairing in Ni--Ga-bilayer junctions
• Magnetoelectric effects in superconductor/ferromagnet bilayers
• Heat transport and electron cooling in ballistic normal-metal/spin-filter/superconductor junctions
• Non-linear spin torque, pumping and cooling in superconductor/ferromagnet systems
• Charge and Spin Supercurrents in Magnetic Josephson Junctions with Spin Filters and Domain Walls
• Chirality and spin transformation of triplet Cooper pairs upon interaction with singlet condensate
• Josephson effect in multi-terminal superconductor-ferromagnet junctions coupled via triplet components
• Spin-orbit pumping
• Static and dynamic properties of Josephson weak links with singlet and triplet coupling
• Anomalous Andreev interferometer: Study of an anomalous Josephson junction coupled to a normal wire
• Excess current in ferromagnet-superconductor structures with fully polarized triplet component
• Spontaneous symmetry breaking-induced thermospin effect in superconducting tunnel junctions