Spin-orbit torque switching without an external field using interlayer exchange coupling.

Area of Science:

• Spintronics
• Materials Science
• Solid State Physics

Background:

• Spin-orbit torque (SOT) offers an alternative to spin-transfer torque (STT) for magnetic devices like MRAM.
• Current SOT switching methods often require an impractical external symmetry-breaking bias field.

Purpose of the Study:

• To demonstrate robust zero-field SOT switching of a perpendicular ferromagnetic free layer.
• To overcome the limitations of external bias fields in spintronic applications.

Main Methods:

• Utilized magnetic coupling between a perpendicular CoFe free layer and an in-plane exchange-biased CoFe layer.
• Employed a nonmagnetic Ru or Pt spacer to mediate the coupling.
• Investigated the influence of current polarity and interlayer exchange coupling (IEC) sign on switching behavior.

Main Results:

• Achieved deterministic SOT switching without an external bias field.
• Demonstrated that the free layer's magnetic state is controlled by current polarity and IEC.
• Showcased a scalable strategy for bias-field-free SOT switching.

Conclusions:

• The proposed method enables practical, zero-field SOT switching for spintronic devices.
• This approach combines high storage density and endurance with low power consumption.
• Offers a scalable solution for next-generation MRAM and other spintronic applications.