Ground states and magnonics in orthogonally-coupled symmetric all-antiferromagnetic junctions

TL;DR

This paper explores the complex ground states and magnon behaviors in orthogonally-coupled all-antiferromagnetic junctions, revealing novel phase transitions, magnon couplings, and controllable spin wave polarization.

Contribution

It uncovers a new MRS phase resulting from spin reorientation and details magnon interactions and polarization control in these junctions, advancing understanding of antiferromagnetic spin dynamics.

Findings

Identification of the MRS phase with mirror-reflection symmetry

Magnon couplings emerge under oblique dc fields leading to anticrossings

Linearly polarized spin waves with controllable polarization directions

Abstract

In this work, the rich ground-state structure of orthogonally-coupled symmetric all-antiferromagnetic junctions with easy-plane anisotropy is reported. Spin reorientation process rather than the traditional spin flop (SF) occurs, resulting in a novel phase in which N\'{e}el vectors preserve the mirror-reflection symmetry (termed as ``MRS phase"). The phase transitions between SF and MRS phases can be either the first- or second-order. After disturbed by external stimuli, magnons with different parities emerge. For in-plane dc fields, no couplings between magnons occur. When dc fields become oblique, coherent couplings between magnons with opposite parity emerge, leading to anticrossings in resonance frequencies. However, self-hybridization among magnons with the same parity never happens. More interestingly, spin waves based on MRS phase are linearly polarized and their polarization directions can be fine controlled.