Bi-directional high speed domain wall motion in perpendicular magnetic anisotropy Co/Pt double stack structures

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Co/Pt double stack wires with Ta capping offer enhanced thermal stability and perpendicular magnetic anisotropy (PMA).
• Spin-orbit torque (SOT) is a key mechanism for manipulating magnetic domain walls.

Purpose of the Study:

• To investigate bidirectional domain wall motion in Co/Pt double stack wires.
• To enhance domain wall velocity through controlled Dzyaloshinskii-Moriya interaction (DMI) and spin-orbit torque (SOT).

Main Methods:

• Utilized a hard-axis magnetic field to control the Dzyaloshinskii-Moriya interaction (DMI) direction.
• Varied Pt spacer thickness and Ta capping thickness to study their effects on domain wall velocity.
• Applied current densities up to 1 × 10^12 A/m^2.

Main Results:

• Achieved bidirectional domain wall motion along and against current flow.
• Observed enhanced domain wall velocity (up to 530 m/s) when the hard-axis field favored DMI and aligned with current flow.
• Velocity decreased with increased Pt spacer thickness and increased with Ta capping thickness.
• Prevented Walker breakdown through low anisotropy and hard-axis field application.

Conclusions:

• The Co/Pt double stack with Ta capping enables efficient bidirectional domain wall motion.
• Optimizing DMI and SOT via magnetic fields and material composition is crucial for high-speed domain wall manipulation.
• This approach shows promise for advanced spintronic device applications.