Dephasing of Transverse Spin Current in Ferrimagnetic Alloys

Youngmin Lim (1) , Behrouz Khodadadi (1) , Jie-Fang Li (1) , Dwight Viehland (1) , Aurelien Manchon (2) , Satoru Emori (1)

1 Virginia Tech [Blacksburg]
2 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille

It has been predicted that transverse spin current can propagate coherently (without dephasing) over a long distance in antiferromagnetically ordered metals. Here, we estimate the dephasing length of transverse spin current in ferrimagnetic CoGd alloys by spin pumping measurements across the compensation point. A modified drift-diffusion model, which accounts for spin-current transmission through the ferrimagnet, reveals that the dephasing length is about 4-5 times longer in nearly compensated CoGd than in ferromagnetic metals. This finding suggests that antiferromagnetic order can mitigate spin dephasingin a manner analogous to spin echo rephasing for nuclear and qubit spin systemseven in structurally disordered alloys at room temperature. We also find evidence that transverse spin current interacts more strongly with the Co sublattice than the Gd sublattice. Our results provide fundamental insights into the interplay between spin current and antiferromagnetic order, which are crucial for engineering spin torque effects in ferrimagnetic and antiferromagnetic metals.

Domaines: Physique [physics]; Matière Condensée [cond-mat]

Youngmin Lim, Behrouz Khodadadi, Jie-Fang Li, Dwight Viehland, Aurelien Manchon, et al.. Dephasing of Transverse Spin Current in Ferrimagnetic Alloys. Physical Review B, 2021, ⟨10.1103/PhysRevB.103.024443⟩. ⟨hal-03147681⟩