Modulation of Electromagnetic Damping and Charge-Spin Conversion in Pt/Py_100-xGd_x Heterostructure

Area of Science:

• Materials Science
• Condensed Matter Physics
• Spintronics

Background:

• Permalloy (Py) offers excellent soft magnetic properties and low damping, ideal for spin nano-oscillators.
• Low magnetic damping in Py, while beneficial for energy efficiency, limits its use in high-speed spintronic devices.
• Enhancing magnetic damping is key to improving the switching speed of spintronic devices.

Purpose of the Study:

• To investigate the effect of Gadolinium (Gd) doping on the spintronic performance of Permalloy (Py) alloys.
• To explore Gd doping as a method for tuning magnetic damping and spin Hall angle in Py.
• To assess the potential of Py-Gd alloys for advanced spintronic applications.

Main Methods:

• Fabrication of Py_100-xGd_x alloys.
• Characterization using spin-torque ferromagnetic resonance (ST-FMR) measurements.
• Analysis of magnetic damping, linewidth modulation, and spin Hall angle.

Main Results:

• The maximum spin Hall angle reached 0.149 for Py₈₀Gd₂₀, a significant increase from 0.042 in pure Py.
• Gd doping effectively modulated the linewidth magnitude.
• Magnetic damping coefficient increased with Gd content, peaking at 0.051 for 17% Gd, a 2.4-fold rise compared to pure Py.

Conclusions:

• Rare-earth element doping, specifically Gd in Py, is a highly effective strategy for tuning spintronic device performance.
• Py-Gd alloys show promise for developing highly efficient spin-orbit torque (SOT) devices.
• Tuning magnetic damping in Py-Gd alloys has significant implications for enhancing magnetization switching speed and reducing drive current density.