Team Members: Zalman Birman, Roi Menasheof

Supervisors / Mentors: Assist. Prof. Amir Capua

 

The rapid growth of data-intensive technologies has spurred significant advancements in memory device architectures, driving demand for faster, more energy-efficient, and durable solutions. Magnetoresistive Random-Access Memory (MRAM) has emerged as a promising alternative, offering non-volatility and high endurance. However, to compete in the increasingly competitive memory market, MRAM must overcome key performance limitations—necessitating novel concepts and mechanisms for writing and storing data.

Current MRAM technologies rely on Magnetic Tunnel Junctions (MTJs) as the fundamental storage element, with data writing achieved through either Spin-Transfer Torque (STT) or Spin-Orbit Torque (SOT). While STT is compact, its shared read/write path introduces reliability and endurance concerns. SOT improves this by decoupling read and write operations but often requires higher dynamic power, reducing its energy efficiency. Over the past year, researchers at the Spintronics Lab demonstrated that a circular optical magnetic field can induce magnetic torque, which led us to hypothesize that a circular spin current could produce a similar effect. Our project aims to provide the first experimental demonstration of this mechanism.

To show this, we designed an experiment in which a ferromagnetic layer—representing the MTJ's free layer—is placed atop a heavy metal substrate. A circular spin current is generated in the heavy metal by injecting RF currents at two points with a controlled phase difference. In our preliminary work, we utilized anisotropic magnetoresistance (AMR) measurements to assess magnetization changes, followed by a comprehensive set of RF phase sweeps, frequency and power variations, and tests under differing external magnetic fields. Future efforts will explore a wider range of magnetic materials, heavy-metal underlayers, and geometrical configurations to further characterize and validate the effect.