Josephson-like spin current in junctions composed of antiferromagnets and ferromagnets

Abstract

We study Josephson-like junctions formed by materials with antiferromagnetic (AF) order parameters. As an antiferromagnet, we consider a two-band material in which a spin density wave (SDW) arises. This could be Fe-based pnictides in the temperature interval $T_{\text{c}}\le T\le T_N$, where $T_c$ and $T_N$ are the critical temperatures for the superconducting and antiferromagnetic transitions, respectively. The spin current $j_{\text{Sp}}$ in AF/F/AF junctions with a ballistic ferromagnetic layer and in tunnel AF/I/AF junctions is calculated. It depends on the angle between the magnetization vectors in the AF leads in the same way as the Josephson current depends on the phase difference of the superconducting order parameters in S/I/S tunnel junctions. It turns out that in AF/F/AF junctions, two components of the SDW order parameter are induced in the F\nobreakdash-layer. One of them oscillates in space with a short period ${\xi }_{\text{F,b}}\sim \hslash v/\mathcal{H}$ while the other decays monotonously from the interfaces over a long distance of the order ${\xi }_{\text{N,b}}=\hslash v/2\pi T$ (where $v$, $\mathcal{H}$ and $T$ are the Fermi velocity, the exchange energy and the temperature, respectively; the subindex $\text{b}$ denotes the ballistic case). This is a clear analogy with the case of Josephson S/F/S junctions with a nonhomogeneous magnetization where short- and long\nobreakdash-range condensate components are induced in the F\nobreakdash-layer. However, in contrast to the charge Josephson current in S/F/S junctions, the spin current in AF/F/AF junctions is not constant in space, but oscillates in the ballistic F\nobreakdash-layer. We also calculate the dependence of $j_{\text{Sp}}$ on the deviation from the ideal nesting in the AF/I/AF junctions.

10 pages, 8 figures; Typos corrected; Journal reference added

References in corpus (8)

• A spin triplet supercurrent through the half-metallic ferromagnet CrO2
• Superconductivity and spin-density-waves in multi-band metals
• Interplay between magnetism and superconductivity in Fe-pnictides
• Valley density-wave and multiband superconductivity in Fe-pnictides
• Spin Josephson effect in ferromagnet/ferromagnet tunnel junctions
• Phase diagram of iron-pnictides if doping acts as a disorder
• Quasiclassical description of a superconductor with a spin density wave
• Generalized DC and AC Josephson effects in antiferromagnets and in antiferromagnetic d-wave superconductors

Cited by in corpus (12)

• Electronic transport through ferromagnetic and superconducting junctions with spin-filter tunneling barriers
• Spin splitting induced in a superconductor by an antiferromagnetic insulator
• Nematic versus ferromagnetic spin filtering of triplet Cooper pairs in superconducting spintronics
• Superconducting proximity effect and long-ranged triplets in dirty metallic antiferromagnets
• Dissipationless Spin Current between Two Coupled Ferromagnets
• Flux Quantization Due to Monopole and Dipole Currents
• Realization of the $\pi$-state in junctions formed by multi-band superconductors with a spin-density-wave
• Monopole Josephson Effects in a Dirac Spin Liquid
• Theory of generalized Josephson effects
• Spin Current in Junctions composed of Multi-band Superconductors with a Spin-density Wave
• Time-dependent equation for the magnetic order parameter near the quantum critical point in multiband superconductors with a spin density wave
• Josephson-like magnetic tunnel junction -- transition from classical to quantum regime