Spin Swapping for an Exchange Magnon Spin Current

TL;DR

This paper introduces a novel spin swapping effect for exchange magnon spin currents in ferromagnetic materials, demonstrating how excitation of one current can generate a secondary current with different polarization, leading to measurable voltages.

Contribution

It proposes a new spin swapping mechanism for exchange magnon spin currents in ferromagnets with in-plane anisotropy, highlighting the role of interface exchange coupling.

Findings

Exchange magnon spin current induces measurable inverse spin Hall voltage.

Spin swapping effect depends on interface exchange coupling.

Secondary spin current has in-plane polarization, different from the primary.

Abstract

We propose the spin swapping effect for an exchange magnon spin current in a perpendicularly magnetized ferromagnetic medium with in plane anisotropy on the surface. The excitation of a magnon current flowing along an in-plane direction with an out-of-plane spin polarization leads to the generation of a secondary exchange spin current propagating along the out-of-plane direction, characterized by an in-plane spin polarization. The resulting exchange magnon spin current can induce an inverse spin Hall voltage of micro-volts. The exchange coupling at the interface between regions with different magnetic anisotropies plays a crucial role in generating the spin swapping effect. This is in contrast to the recently reported spin swapping for an exchange spin current in a canted antiferromagnet due to the Dzyaloshiskii-Moriya interaction.