Capturing Coherent Magnons by Tip-Assisted Terahertz Spectroscopy.

Park, Byung Cheol; Oh, Sang Hyup; Choi, Young Jai; Ha, Taewoo · Nano Lett · 2024

basic_science · Level V

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Abstract

Our study highlights the versatility of tip-assisted terahertz spectroscopy in probing coherent magnons, the elementary quanta of spin waves in magnetic materials. We identify two distinct coherent magnon types in canted antiferromagnet YFeO<sub>3</sub>. The remarkable consistency with far-field terahertz spectroscopy in crucial magnon parameters, such as coherence time and resonance frequency, firmly establishes the credibility of tip-assisted terahertz spectroscopy. Notably, we capture more coherent ferromagnetic magnons near the sample surface, underscoring the strength of the technique. This approach paves the way for local, free-standing, and real-space investigations of spin waves in solid magnets.