Magnon-mediated angular-momentum flow in antiferromagnets may become a design element for energy-efficient, low-dissipation and high-speed spintronic devices. Here, terahertz emission measurements in magnetic multilayers unveil a superluminal-like magnon velocity of ~650 km s–1 in the antiferromagnetic insulator NiO at nanoscale distances.
- Kyusup Lee
- Dong-Kyu Lee
- Hyunsoo Yang