Nanometer scale observation of high efficiency thermally assisted current-driven domain wall depinning

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Domain walls (DWs) are critical for magnetic memory devices.
• Controlling DW motion with spin currents is a key spintronics challenge.
• Understanding DW depinning dynamics is essential for device optimization.

Purpose of the Study:

• To observe and analyze the depinning of narrow domain walls (DWs) at the nanometer scale.
• To investigate the influence of spin current on DW motion in specific magnetic thin films.
• To quantify the efficiency of current-driven DW motion assisted by thermal fluctuations.

Main Methods:

• Fabrication of thin films with perpendicular magnetic anisotropy.
• Creation of approximately 12 nm wide 1D Bloch domain walls.
• Magnetotransport measurements to probe DW depinning and motion.
• Analysis of thermally assisted current-driven DW movement between pinning sites.

Main Results:

• Demonstrated nanometer-scale observation of DW depinning under spin current.
• Observed thermally assisted current-driven DW motion between pinning sites as close as 20 nm.
• Measured significantly higher efficiency for current-driven DW motion in perpendicular magnetic anisotropy films compared to in-plane films.
• Achieved control of DW motion at the nanometer scale using low current densities.

Conclusions:

• Spin current efficiently drives DW motion in narrow 1D Bloch DWs in perpendicular magnetic anisotropy films.
• Thermal fluctuations play a crucial role in enhancing DW depinning efficiency.
• This work enables precise nanometer-scale control of DW motion at low current densities, relevant for advanced magnetic devices.