Enhanced Spin-Orbit Torque Efficiency in Platinum-Gadolinium Oxide Nanocomposite Films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Spintronics

Background:

• Spin-orbit torque (SOT) is crucial for magnetization manipulation in spintronic devices.
• Current SOT methods suffer from low energy efficiency due to limited damping-like SOT (DL-SOT) efficiency.
• Developing materials with enhanced spin Hall effect is key to improving SOT performance.

Purpose of the Study:

• To develop novel spin Hall materials with significantly enhanced DL-SOT efficiency.
• To investigate the impact of rare earth oxide doping on platinum's spin Hall properties.
• To assess the potential of these new materials for low-power SOT applications.

Main Methods:

• Fabrication of Pt$_{0.70}$(GdO$_{}$)$_{0.30}$ thin films using magnetron sputtering.
• Measurement of DL-SOT efficiency using spin-torque ferromagnetic resonance (ST-FMR).
• Characterization of current-induced magnetization switching properties.
• Theoretical analysis to understand the underlying physics of the enhanced spin Hall effect.

Main Results:

• Achieved a DL-SOT efficiency of 0.35 ± 0.013 in Pt$_{0.70}$(GdO$_{}$)$_{0.30}$, approximately five times higher than pure Pt.
• Observed a significantly reduced critical switching current density of 8.0 × 10$^{6}$ A·cm$^{-2}$.
• Theoretical analysis attributed the enhancement to a strong side jump effect induced by GdO$_{}$ impurities.

Conclusions:

• Pt$_{1-x}$(GdO$_{x}$)$_{x}$ materials exhibit a substantial enhancement in DL-SOT efficiency.
• These materials are promising for developing energy-efficient SOT devices.
• Rare earth oxide doping offers a viable strategy to engineer spin Hall angles and improve SOT performance.