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MA: Fachverband Magnetismus

MA 27: Ultrafast Magnetization Effects I

MA 27.6: Vortrag

Mittwoch, 11. März 2026, 11:15–11:30, HSZ/0004

Spin-lattice coupling control of ultrafast order melting in antiferromagnetic insulators — Aleksandr Buzdakov¹, •Ravi Kaushik¹, Nikolai Khokhlov², Johan Mentink², Sergey Artyukhin¹, and Aleksei Kimel² — ¹Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy — ²Radboud University Nijmegen, Institute for Molecules and Materials, 6525 AJ Nijmegen, The Netherlands

Ultrafast order melting in magnetic insulators is governed by two processes: intrinsic intra-spin relaxation and spin-lattice energy transfer. Antiferromagnets, which lack net magnetization, can in principle evade angular-momentum constraints and display markedly faster order-parameter dynamics than ferromagnets, but experimental rates vary widely across materials. Here we combine first-principles magnetostriction calculations, phonon and magnon spectral analysis, atomistic spin-dynamics simulations and time-resolved second-harmonic generation to disentangle these pathways and explain material-dependent disparities. Focusing on two structurally similar antiferromagnets, Cr₂O₃ and FeBO₃, we show that the strength of spin-phonon coupling - revealed by magnetostrictive response and phonon-magnon spectral overlap - dictates the dramatic difference in order-melting rates. We also achieved accelerated dynamics in Cr₂O₃ and show sub-2-ps order melting in both experiment and simulation. Our results identify spin-phonon coupling as the decisive control parameter for ultrafast antiferromagnetic dynamics and provide a practical framework to design faster switching in antiferromagnetic spintronic devices.

Keywords: Spin-phonon coupling; Ultrafast magnetism; Magnetostriction; Antiferromagnetic insulators; Second-harmonic generation