Efficient and controlled domain wall nucleation for magnetic shift registers

Area of Science:

• Spintronics
• Materials Science
• Nanotechnology

Background:

• Ultrathin ferromagnetic strips are key for memory devices, storing data in magnetic domains.
• Efficient creation and manipulation of domain walls are crucial for practical device applications.
• Chiral domain walls in asymmetric multilayers show high-velocity current-driven dynamics.

Purpose of the Study:

• To propose and demonstrate an efficient scheme for nucleating domain walls in ferromagnetic strips.
• To enable continuous and synchronous injection of domain walls for memory device operation.
• To facilitate controlled writing of binary information using domain wall dynamics.

Main Methods:

• Utilized symmetry of spin orbit torques for domain wall nucleation.
• Employed trains of short sub-nanosecond current pulses in a double bit line.
• Generated localized longitudinal Oersted fields and injected current through an underlying heavy metal layer.

Main Results:

• Demonstrated controlled injection of a series of domain walls.
• Achieved efficient domain wall nucleation assisted by both spin orbit torque and Oersted field.
• Showcased a method for controlled writing of binary information.

Conclusions:

• The proposed scheme offers an efficient and simple method for domain wall nucleation.
• This technique is vital for the practical design of domain wall shift registers.
• Enables controlled binary information writing for next-generation memory devices.