Magnetic exchange interaction in spin-valve with chiral spin-triplet superconductor

TL;DR

This paper explores how chiral spin-triplet superconductors influence magnetic interactions in spin-valves, revealing anisotropic exchange effects and the potential to switch between collinear and noncollinear magnetic states.

Contribution

It provides a self-consistent analysis of magnetic coupling in spin-valves with chiral spin-triplet superconductors, highlighting anisotropic interactions and magnetic state transitions.

Findings

Magnetic coupling exhibits anisotropic character due to spin-triplet pairing.

Transitions between collinear and noncollinear magnetic configurations are possible.

The exchange interaction depends on magnetization amplitude and spacer length.

Abstract

The coupling between two ferromagnets separated by a superconductor has been mostly investigated for the case of Cooper pairs with spin-singlet symmetry. Here, we consider a spin-triplet superconductor with chiral pairing. By full self-consistent analysis of the spatial dependent superconducting order parameter, we determine the magnetic ground state of the superconducting spin valve. The study is performed by investigating the role of the orientation and strength of the magnetization in the ferromagnets including spin-valve asymmetries in the magnetic configurations. Due to the nonvanishing angular momentum of the spin-triplet Cooper pairs we demonstrate that the induced magnetic coupling has an anisotropic character and a structure that can favor collinear or noncollinear magnetic orientations, thus mimicking a magnetic interaction of the Heisenberg or Dzyaloshinskii-Moriya type, respectively. We investigate the role of the physical parameters controlling the character of the magnetic exchange: the amplitude of the magnetization in the ferromagnets and the length of the superconducting spacer in the spin valve. Our study demonstrates that spin-triplet superconductors can be employed to devise anisotropic magnetic exchange and to allow for transitions in the spin-valve state from a collinear to noncollinear magnetic configuration.