Picosecond acoustic-excitation-driven ultrafast magnetization dynamics in dielectric Bi-substituted yttrium iron garnet

Marwan Deb (1) , Elena Popova (2) , Michel Hehn (1) , Niels Keller (2) , Stéphane Mangin (1) , Grégory Malinowski (1)

1 IJL - Institut Jean Lamour
2 GEMAC - Groupe d'Etude de la Matière Condensée

Using femtosecond optical pulses, we have investigated the ultrafast magnetization dynamics induced in a dielectric film of bismuth-substituted yttrium iron garnet (Bi-YIG) buried below a thick Cu/Pt metallic bilayer. We show that exciting the sample from the Pt surface launches an acoustic strain pulse propagating into the garnet film. We discovered that this strain pulse induces a coherent magnetization precession in the Bi-YIG at the frequency of the ferromagnetic resonance. The observed phenomena can be explained by strain-induced changes of magnetocrystalline anisotropy via the inverse magnetostriction effect. These findings open perspectives toward the control of the magnetization in magnetic garnets embedded in complex heterostructure devices

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Marwan Deb, Elena Popova, Michel Hehn, Niels Keller, Stéphane Mangin, et al.. Picosecond acoustic-excitation-driven ultrafast magnetization dynamics in dielectric Bi-substituted yttrium iron garnet. Physical Review B, 2018, 98 (17), pp.174407. ⟨10.1103/PhysRevB.98.174407⟩. ⟨hal-02068295⟩