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arXiv · 2607.05946

Orientation-resolved ultrafast spin reorientation dynamics in ferrimagnetic DyCo$_5$

Johanna Richter·Martin Hennecke·Martin Schmidbauer·Ilie Radu·Clemens von Korff Schmising·Stefan Eisebitt
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Abstract

Under quasi-static conditions, ferrimagnetic DyCo$_5$ thin films exhibit a thermally induced spin-reorientation transition, in which the equilibrium magnetization changes from an out-of-plane to an in-plane orientation, mostly as a result of the competing magnetic anisotropy contributions of the Dy $4f$ rare-earth and Co $3d$ transition-metal sublattices. While this equilibrium transition has been studied, it remains an open question whether such a reorientation can be triggered on ultrafast timescales using femtosecond laser excitation. In this work, we investigate the ultrafast spin-reorientation dynamics in DyCo$_5$. The time-dependent orientation of the magnetization vector following femtosecond laser excitation is quantified by combining polar with transverse magneto-optical Kerr effect (MOKE) measurements in the extreme ultraviolet spectral range, which are sensitive to the out-of-plane and in-plane magnetization component, respectively. Both techniques are implemented at the Co M$_{3,2}$ resonance and are complemented by visible-light MOKE measurements. This combined approach allows us to resolve the canting of the magnetization from an out-of-plane toward an in-plane orientation and to determine the characteristic timescales of the transient spin-reorientation process.

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Johanna Richter, Martin Hennecke, Martin Schmidbauer, Ilie Radu, Clemens von Korff Schmising, Stefan Eisebitt. 2026-07-07. Orientation-resolved ultrafast spin reorientation dynamics in ferrimagnetic DyCo$_5$. https://arxiv.org/abs/2607.05946

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