Switching a Perpendicular Ferromagnetic Layer by Competing Spin Currents

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Controlling magnetism electrically is a key goal in spintronics.
• Current-induced spin-orbit torque (SOT) offers a promising route but typically requires magnetic fields.
• Existing SOT switching methods are limited by the need for external fields or complex setups.

Purpose of the Study:

• To demonstrate magnetic switching using only an in-plane current.
• To overcome limitations of current SOT switching techniques.
• To investigate a novel spintronic device structure for efficient magnetization control.

Main Methods:

• Fabrication of a novel spintronic device structure with two heavy metals.
• Electrical current application to induce spin currents.
• Magnetic domain imaging to observe magnetization switching.
• Analysis of domain wall motion under current stimulus.

Main Results:

• The novel device structure successfully switched perpendicular CoFeB magnetization using only an in-plane current.
• Competing spin currents from the two heavy metals enabled field-free switching.
• Asymmetrical domain wall motion was observed under current, indicating selective switching.

Conclusions:

• The developed structure enables efficient, field-free SOT switching.
• This work challenges conventional understanding of SOT mechanisms.
• The findings pave the way for practical spintronic nonvolatile memory applications.