Spin drift velocity, polarization, and current-driven domain-wall motion in (Ga,Mn)(As,P)

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Ferromagnetic semiconductors are promising for spintronic devices.
• Understanding current-driven domain wall motion is crucial for device applications.
• Perpendicular magnetic anisotropy is key for efficient domain wall manipulation.

Purpose of the Study:

• To investigate current-driven domain-wall motion in (Ga,Mn)(As,P) ferromagnetic semiconductor tracks.
• To explore the relationship between domain-wall velocity and spin drift velocity.
• To analyze the spin transfer torque and current spin polarization.

Main Methods:

• Fabrication of (Ga,Mn)(As,P) ferromagnetic semiconducting tracks.
• Electrical transport measurements to study domain-wall dynamics.
• Temperature-dependent measurements across the ferromagnetic phase.

Main Results:

• A linear steady-state flow regime for domain-wall motion was observed over a wide temperature range (0.1T(c) < T < T(c)).
• Near 0 K, domain-wall velocity equals spin drift velocity, occurring below the intrinsic motion threshold.
• This suggests a nonadiabatic contribution to spin transfer torque.

Conclusions:

• Domain-wall dynamics in (Ga,Mn)(As,P) exhibit a linear flow regime.
• Nonadiabatic spin transfer torque plays a significant role in domain-wall motion at low temperatures.
• The temperature dependence of current spin polarization can be inferred from domain-wall dynamics.