Strongly exchange-coupled and surface-state-modulated magnetization dynamics in Bi2Se3/YIG heterostructures

TL;DR

This study demonstrates strong interfacial exchange coupling and surface-state effects in Bi2Se3/YIG heterostructures, revealing how topological surface states influence magnetization dynamics and potential spintronic applications.

Contribution

It uncovers the role of topological surface states in modulating magnetization dynamics in Bi2Se3/YIG heterostructures, highlighting the thickness dependence and temperature effects.

Findings

Maximum interfacial magnetic anisotropy at 6 QL Bi2Se3

Surface states significantly influence magnetization dynamics

Magnetic proximity effect observed up to 180 K

Abstract

We report strong interfacial exchange coupling in Bi2Se3/yttrium iron garnet (YIG) bilayers manifested as large in-plane interfacial magnetic anisotropy (IMA) and enhancement of damping probed by ferromagnetic resonance (FMR). The IMA and spin mixing conductance reached a maximum when Bi2Se3 was around 6 quintuple-layer (QL) thick. The unconventional Bi2Se3 thickness dependence of the IMA and spin mixing conductance are correlated with the evolution of surface band structure of Bi2Se3, indicating that topological surface states play an important role in the magnetization dynamics of YIG. Temperature-dependent FMR of Bi2Se3/YIG revealed signatures of magnetic proximity effect of $T_c$ as high as 180 K, and an effective field parallel to the YIG magnetization direction at low temperature. Our study sheds light on the effects of topological insulators on magnetization dynamics, essential for development of TI-based spintronic devices.