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MA: Fachverband Magnetismus
MA 31: Poster II
MA 31.19: Poster
Mittwoch, 19. März 2025, 17:00–19:30, P1
Ultrafast magneto-elastic phenomena in highly magnetostrictive materials with systematic variation of anisotropy — •Constantin Walz1, Fried Weber1, Karine Dumesnil2, Alexander von Reppert1, and Matias Bargheer1, 3 — 1Institut für Physik und Astronomie, Universität Potsdam, Germany — 2Institut Jean Lamour, Université Lorraine, Nancy, France — 3Helmholtz-Zentrum Berlin, Germany
Highly magnetostrictive Rare Earth-Iron compounds (REFe2 with RE = Tb, Dy, Tb0.3Dy0.7) are well known for their giant (inverse) magnetostriction, with more than 10−3 lattice constant change when applying a magnetic field. Because of that they are widely used as ultrasonic transducers in the MHz regime. Their laser-induced magnetization dynamics are less explored, though they have potential as field-tunable magneto-acoustic transducers in the GHz regime or even for strain driven magnetization switching. Here we compare polar transient magneto-optical Kerr effect (trMOKE) data on three (110)-oriented REFe2. The rare-earth ion influences the cubic magnetocrystalline anisotropy energy, leading to nontrivial demagnetization and precession responses with opposing signs for Dy and Tb. We discuss non-resonant strain-driven magnetization dynamics that follow the lattice deformation with a delay. Glass-capped TbFe2 films help to disentangle signal contributions from unipolar strain pulses, quasi-static strain and spin disorder.
Keywords: Magnetostriction; Rare Earths; trMOKE; Anisotropy