Y3Fe5O12 spin pumping for quantitative understanding of pure spin transport and spin Hall effect in a broad range of materials (invited)

Abstract

Using Y3Fe5O12 (YIG) thin films grown by our sputtering technique, we study dynamic spin transport in nonmagnetic (NM), ferromagnetic (FM) and antiferromagnetic (AF) materials by ferromagnetic resonance (FMR) spin pumping. From both inverse spin Hall effect (ISHE) and damping enhancement, we determine the spin mixing conductance and spin Hall angle in many metals. Surprisingly, we observe robust spin conduction in AF insulators excited by an adjacent YIG at resonance. This demonstrates that YIG spin pumping is a powerful and versatile tool for understanding spin Hall physics, spin-orbit coupling (SOC), and magnetization dynamics in a broad range of materials.2

Spin Hall torques generated by rare-earth thin films

“…Our work is motivated by theoretical predictions that the spin Hall effect in metals with partially full f (l = 3) orbitals is potentially quite large 27 . In the most naive consideration of the SHE, one might expect that the combination of both large orbital angular momenta and large spins in f -electron atoms might lead to large spin-orbit coupling terms, scaling approximately as l ·s , and consistent with the qualitative trend observed in the 3d, 4d, and 5d transition metals 11,28,29 . Within this simple ansatz, rare-earths near 1/4 and 3/4 filling of the f orbitals are likely candidates for a strong SHE (Fig.…”

High-quality thulium iron garnet films with tunable perpendicular magnetic anisotropy by off-axis sputtering – correlation between magnetic properties and film strain

“…Yttrium iron garnet (YIG) 2–5 and lutetium iron garnet (LuIG) 6 possess ultra-low intrinsic damping constants, which benefits spin transport studies such as long-range spin wave propagation, efficient spin pumping, SOT and spin-torque ferromagnetic resonance (ST-FMR). Moreover, thulium iron garnet (TmIG) films grown on (111)-oriented gadolinium gallium garnet (GGG) substrates were reported to show stress-induced PMA 7,8 .…”

High-quality single-crystal thulium iron garnet films with perpendicular magnetic anisotropy by off-axis sputtering

“…Ferromagnetic insulators (FIs), such as rare earth iron garnets (REIGs), have attracted a great deal of interests recently because of their extremely low intrinsic damping constant of yttrium iron garnet (YIG) [1][2][3][4] and lutetium iron garnet (LuIG), 5 ideal for spin transport studies like long-range spin wave propagation, efficient spin pumping, spin-orbit torque (SOT) and spin-torque ferromagnetic resonance (ST-FMR) in FI-based heterostructures. FI-based heterostructures are preferred over ferromagnetic metal (FM) based heterostructures to circumvent the current shunting effect, thus to avoid complications due to the presence of charge currents in FM.…”