Sub-picosecond exchange-relaxation in the compensated ferrimagnet Mn${}_2$Ru${}_x$Ga

Abstract

We study the demagnetization dynamics of the fully compensated half-metallic ferrimagnet Mn${}_2$Ru${}_x$Ga. While the two antiferromagnetically coupled sublattices are both composed of manganese, they exhibit different temperature dependencies due to their differing local environments. The sublattice magnetization dynamics triggered by femtosecond laser pulses are studied to reveal the roles played by the spin and intersublattice exchange. We find a two-step demagnetization process, similar to the well-established case of Gd(FeCo)${}_3$, where the two Mn-sublattices have different demagnetization rates. The behaviour is analysed using a four-temperature model, assigning different temperatures to the two manganese spin baths. Even in this strongly exchange-coupled system, the two spin reservoirs have considerably different behaviour. The half-metallic nature and strong exchange coupling of Mn${}_2$Ru${}_x$Ga lead to spin angular momentum conservation at much shorter time scales than found for Gd(FeCo)${}_3$ which suggests that low-power, sub-picosecond switching of the net moment of Mn${}_2$Ru${}_x$Ga is possible.

5 pages, 3 figures, J. Phys.: Condens. Matter (2021)

References in corpus (3)

• All-optical control of ferromagnetic thin films and nanostructures
• Ultrafast photo-magnetic recording in transparent medium
• Study of the Effect of Annealing on the Properties of Mn2RuxGa Thin Films

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• Atomistic spin model of single pulse toggle switching in Mn${}_2$Ru${}_x$Ga Heusler alloys
• First-principles insights into all-optical spin switching in the half-metallic Heusler ferrimagnet Mn${}_2$RuGa
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• Optimizing Time-resolved Magneto-optical Kerr Effect for High-fidelity Magnetic Characterization