Enhanced Terahertz Emission Through Orbital‐to‐Charge Conversion in YIG/Pt/CuO x

ABSTRACT The emerging field of orbitronics aims to control the electron orbital momentum and push its applications into the terahertz (THz) frequency range. However, the ultrafast generation of the orbital current in ferromagnetic insulators has remained unexplored. Here, we report that the THz signal of yttrium iron garnet (YIG)/Pt/CuO x is 1.5 times larger than that of YIG/Pt, which can be attributed to the orbital‐to‐charge conversion at the Pt/CuO x by inverse orbital Rashba–Edelstein effect. The magnons generated by the femtosecond laser in the ferrite YIG are the source of the orbital current. Our work provides technical insights into the design of ultrafast orbitronic devices comprising of ferromagnetic insulators, as well as facilitates the development of efficient spintronic THz emitters based on orbital‐to‐charge conversion.