Rashba-type spin-orbit coupling in two-dimensional electron gases (2DEGs) is of great interest for efficient charge-to-spin conversion. Ultrathin ${\mathrm{La}\mathrm{Ti}\mathrm{O}}_3$ films on ${\mathrm{Sr}\mathrm{Ti}\mathrm{O}}_3$ (LTO/STO) give rise to a 2DEG and have previously been shown to exhibit giant Rashba spin-orbit coupling, making this a promising platform for demonstrating efficient charge-to-spin conversion. For this reason, we fabricated $\mathrm{Co}\mathrm{Fe}\mathrm{B}/{\mathrm{La}\mathrm{Ti}\mathrm{O}}_3/{\mathrm{Sr}\mathrm{Ti}\mathrm{O}}_3$ heterostructures to understand how spin-charge interconversion occurs as a function of temperature in these systems. The spin-to-charge conversion in LTO/STO can be understood in terms of Rashba spin-orbit coupling and thermoelectric contributions. Ferromagnetic resonance shows spin-current absorption by the LTO/STO interface, which is reduced as the LTO layer thickness increases. Through second-harmonic Hall measurements, we observe a damping-like torque efficiency of approximately $0.30$ at 50 K, which increases sharply to approximately $8.6$ at 10 K. Our results characterize the factors contributing to spin-charge conversion in these heterostructures, which is important for the incorporation of 2DEGs with strong Rashba-type spin-orbit coupling into spintronic systems.

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• Rashba coupling
• Spintronics
• Heterostructures
• Interfaces
• Magnetic multilayers
• Transition metal oxides
• Two-dimensional electron gas
• Ferromagnetic resonance