Enhancing the emission from trilayer spintronic terahertz emitters by Cu alloying

Recent interest in spintonic terahertz (THz) emitters has been driven by their simplicity, low cost and ability to generate high electric field amplitudes over a broad, gapless spectral bandwidth. Here we report on strategies to optimize the amplitude of THz electric fields from spintronic emitters. Specifically, we explore the effect of Cu alloying on the emission from trilayer, W/CoFeB/Pt, emitters. By introducing Cu into both the W and Pt layers we show a significant increase in emission of ∼27% compared to a trilayer without Cu, and an increase of ∼61% compared to a CoFeB/Pt bilayer emitter. These results demonstrate significant potential for improved THz emission by optimizing the metallic layer via alloying with Cu.