Dependence of spin-orbit torque effective fields on magnetization uniformity in Ta/Co/Pt structure

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Spin-orbit torque (SOT) is crucial for spintronic devices.
• SOT effective fields (field-like and damping-like) are known to depend on layer thicknesses in heterostructures.
• Understanding SOT dependence on other material properties is essential for device optimization.

Purpose of the Study:

• To investigate the influence of magnetization uniformity on SOT effective fields.
• To decouple the effect of magnetization uniformity from layer thickness variations.
• To elucidate the role of the spin Hall effect in SOT under varying magnetization uniformity.

Main Methods:

• Fabrication of Ta/Co/Pt wire structures with controlled Co layer magnetization uniformity.
• Concurrent variation of magnetization uniformity and characterization of SOT effective fields.
• Experimental analysis to isolate the impact of magnetization uniformity on field-like and damping-like SOT terms.

Main Results:

• The field-like SOT effective field term decreases as Co magnetization uniformity increases.
• The damping-like SOT effective field term increases with increasing Co magnetization uniformity.
• A clear correlation between magnetization uniformity and SOT effective fields was established, independent of layer thickness.

Conclusions:

• Magnetization uniformity is a critical parameter influencing SOT effective fields in Ta/Co/Pt systems.
• The observed trends are attributed to the spin Hall effect's contribution to SOT.
• This finding provides new insights for engineering SOT in spintronic devices.