Current-Induced Spin Torques on Single GdFeCo Magnetic Layers.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Spintronics utilizes spin-orbit coupling (SOC) for spin currents and torques, often relying on 3d metals with small SOC.
• Conventional spintronics employs 5d heavy metals (e.g., Pt) for enhanced SOC, but this study introduces an alternative.
• Inversion symmetry breaking is crucial for Rashba and Dzyaloshinskii-Moriya interactions in spintronic devices.

Purpose of the Study:

• To introduce novel material architectures for high-performance spintronics that exclude nonmagnetic 5d heavy metals.
• To demonstrate strong current-induced torques ('self-torques') in single ferrimagnetic GdFeCo layers.
• To investigate the spin current emission properties of GdFeCo layers.

Main Methods:

• Fabrication of material architectures excluding nonmagnetic 5d heavy metals.
• Experimental demonstration of current-induced torques on single ferrimagnetic GdFeCo layers.
• Characterization of spin current generation and spin-orbit coupling effects.
• Measurements of spin anomalous Hall effect and spin Hall effect symmetries.

Main Results:

• Demonstrated very strong current-induced 'self-torques' on single GdFeCo layers, attributed to Gd 5d SOC and interface-engineered inversion symmetry breaking.
• Observed enhancement of these self-torques around the magnetization compensation temperature.
• Determined very large spin current emission from GdFeCo, with 80% (20%) spin anomalous Hall effect (spin Hall effect) symmetry.

Conclusions:

• A new material platform for spintronics is presented, enabling 'self-torques' on single magnetic layers without heavy metals.
• This platform facilitates efficient spin current generation directly from magnetic layers.
• The findings open new avenues for advanced spintronic device designs and functionalities.