Orbital Torque in Rare-Earth Transition-Metal Ferrimagnets

Abstract

Orbital currents have recently emerged as a promising tool to achieve electrical control of the magnetization in thin-film ferromagnets. Efficient orbital-to-spin conversion is required in order to torque the magnetization. Here we show that the injection of an orbital current in a ferrimagnetic GdyCo100-y alloy generates strong orbital torques whose sign and magnitude can be tuned by changing the Gd content and temperature. The effective spin-orbital Hall angle reaches up to -0.25 in a GdyCo100-y/CuOx bilayer compared to +0.03 in Co/CuOx and +0.13 in GdyCo100-y/Pt. This behavior is attributed to the local orbital-to-spin conversion taking place at the Gd sites, which is about five times stronger and of the opposite sign relative to Co. Furthermore, we observe a manyfold increase in the net orbital torque at low temperature, which we attribute to the improved conversion efficiency following the magnetic ordering of the Gd and Co sublattices.

References in corpus (10)

• Study of Intrinsic Spin Hall Effect and Orbital Hall Effect in 4d- and 5d- Transition Metals
• Observation of the orbital Hall effect in a light metal Ti
• Giant Orbital Hall Effect in Transition Metals: Origin of Large Spin and Anomalous Hall Effects
• Observation of long-range orbital transport and giant orbital torque
• Giant orbital Hall effect and orbital-to-spin conversion in 3d, 5d, and 4f metallic heterostructures
• Observation of the Orbital Rashba-Edelstein Magnetoresistance
• Orbital Rashba effect in surface oxidized Cu film
• Orbital Hanle Magnetoresistance in a 3d Transition Metal
• Strong variation of spin-orbit torques with relative spin relaxation rates in ferrimagnets
• Unidirectional orbital magnetoresistance in light metal/ferromagnet bilayers

Cited by in corpus (8)

• Mitigation of Gilbert Damping in the CoFe/CuOx Orbital Torque System
• Extrinsic Orbital Hall Effect: Orbital Skew Scattering and Crossover Between Diffusive and Intrinsic Orbital Transport
• Orbital Pumping in Ferrimagnetic Insulators
• Nonlocal Electrical Detection of Reciprocal Orbital Edelstein Effect
• Coexistent multifractal mesoscopic fluctuations in Integer Quantum Hall Transition and in Orbital Hall Transition
• Spin current symmetries generated by GdFeCo ferrimagnet across its magnetisation compensation temperature
• Beyond spin-1/2: Multipolar spin-orbit coupling in noncentrosymmetric crystals with time-reversal symmetry
• Orbital torques and orbital pumping in two-dimensional rare-earth dichalcogenides