Giant Spin Hall Effect in Cu-Tb Alloy Thin Films

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• The spin Hall effect (SHE) is a key phenomenon in spintronics for generating spin currents.
• Investigating novel materials for efficient spin current generation is crucial for advancing spintronic devices.

Purpose of the Study:

• To explore the potential of CuTb alloys for giant spin current generation via SHE.
• To characterize the spin Hall effect and related parameters in CuTb-based heterostructures.

Main Methods:

• Fabrication of magnetic heterostructures incorporating CuTb alloys.
• Electrical characterization to measure spin Hall angles and related spintronic parameters.
• Analysis of scattering mechanisms contributing to the spin Hall effect.

Main Results:

• Achieved a maximum spin Hall angle of -0.35 ± 0.02 in Cu_0.39Tb_0.61.
• Identified the dominant scattering mechanism (skew scattering vs. side jump) based on Tb concentration.
• Determined spin diffusion length (2.5 ± 0.3 nm) and spin-mixing conductance ((24.2 ± 1.0) × 10¹⁵ cm^-2) for Cu_0.53Tb_0.47.
• Measured interfacial spin transparency (0.55 ± 0.03) at the CoFeB/Cu_0.53Tb_0.47 interface.

Conclusions:

• CuTb alloys exhibit giant spin current generation, demonstrating significant potential for spintronic applications.
• Rare-earth metals like terbium can be effectively utilized as spin Hall materials in advanced devices.
• The study provides critical parameters for designing and optimizing spin-orbit torque (SOT) devices.