Magnetic anisotropy modification in a garnet ferrimagnet by interfacial spin orbit coupling

Y₃Fe₅O₁₂ (YIG) is a ferrimagnetic insulator with substantial potential in realizing pure spin-based information processing and storage exceptionally low Gilbert damping. This contributes to its potential for enabling pure spin-based information processing and storage. Interfacial interactions can induce magnetic anisotropy is in this cubic material. When a nonmagnetic heavy metal is deposited on YIG, an additional easy-plane anisotropy arising from the Rashba spin orbit coupling (SOC) is induced. Here we report that a perpendicular magnetic anisotropy (PMA) is induced at the interface between YIG and a low symmetry high SOC semimetal, WTe₂. The PMA in the YIG/WTe₂ heterostructure is rooted in the broken inversion symmetry in the WTe₂ crystal lattice, which gives rise to an additional SOC that was previously reported to enable an out-of-plane spin orbit torque. In addition, we study the spin pumping across the YIG/WTe₂ interface and find that its strength is independent of the WTe₂ thickness. Our study suggests that SOC arising from the broken crystalline symmetry in WTe₂ plays crucial role in modifying the interfacial magnetic anisotropy and in spin relaxation at the interface.