Ultrafast Laser-Induced Melting of Long-Range Magnetic Order in Multiferroic TbMnO3

Abstract

We performed ultrafast time-resolved near-infrared pump, resonant soft X-ray diffraction probe measurements to investigate the coupling between the photoexcited electronic system and the spin cycloid magnetic order in multiferroic TbMnO3 at low temperatures. We observe melting of the long range antiferromagnetic order at low excitation fluences with a decay time constant of 22.3 +- 1.1 ps, which is much slower than the ~1 ps melting times previously observed in other systems. To explain the data we propose a simple model of the melting process where the pump laser pulse directly excites the electronic system, which then leads to an increase in the effective temperature of the spin system via a slower relaxation mechanism. Despite this apparent increase in the effective spin temperature, we do not observe changes in the wavevector q of the antiferromagnetic spin order that would typically correlate with an increase in temperature under equilibrium conditions. We suggest that this behavior results from the extremely low magnon group velocity that hinders a change in the spin-spiral wavevector on these time scales.

9 pages, 4 figures

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Cited by in corpus (10)

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• Lattice-Mediated Magnetic Order Melting in TbMnO3
• Directly probing spin dynamics in insulating antiferromagnets using ultrashort terahertz pulses
• Dynamic pathway of the photoinduced phase transition of TbMnO${}_3$
• Photo-creating supercooled spiral-spin states in a multiferroic manganite
• Photoinduced structural dynamics of multiferroic TbMnO${}_3$
• Properties and challenges of hot-phonon physics in metals: MgB${}_2$ and other compounds
• Ultrafast signatures of spin and orbital order in antiferromagnetic $\alpha$-Sr${}_2$CrO${}_4$