Magnetoelastic Spin-Orbit-Torque Ramdom-Access Memory (MeSOT-RAM) System

Case 2018-202

UCLA researchers in the Department of Mechanical Engineering have developed a non-volatile random-access memory (RAM) device which uses magnetoelastic spin-orbit torque (MeSOT).

BACKGROUND

Magnetic RAM (MRAM) is a promising memory technology because it possesses non-volatility, high density, and high scalability. Spin Orbit Torque (SOT) MRAM is gaining interest as an energy efficient method to control magnetization in magnetic memory devices. However, they can only control memory bit with in-plane anisotropy, which has low thermal stability and a large footprint. Memory bits with perpendicular magnetic anisotropy (PMA) have demonstrated higher thermal stability and smaller footprint, but SOT memory bits cannot be written/read with PMA. Therefore, a random-access memory system for writing/reading memory bits with PMA is needed.

INNOVATION

UCLA researchers have developed a non-volatile RAM device which uses magnetoelastic spin-orbit torque to write data more efficiently. The hybrid magnetization control mechanism combines SOT and multiferroics to improve endurance and energy efficiency. The design combines efficient multiferroic control with the directionality of SOT. High thermal stability and small footprint are also achieved through perpendicular memory bits. The separate writing and reading pathway design provides relatively low write error rate. Moreover, the fabrication process is simplified by avoiding the nano-patterning of layer components.

APPLICATIONS

• Magnetic memory devices

ADVANTAGES

• High endurance –writing current does not penetrate the insulating layer
• Better energy efficiency than spin-transfer torque method
• High thermal stability and small footprint
• Directional and deterministic control of magnetization
• Random-access reading/writing abilities
• High readout tunnel magnetoresistance ratio
• Relatively low write error rate
• Simplified fabrication process

RELATED MATERIALS

• Wang, Q., Domann, J., Yu, G., Barra, A., Wang, K., and Carman, G., A hybrid magnetic random-access memory using spin-orbit torque and multiferroics, Bulletin of the American Physical Society, 2018.
• Wang, Q., Domann, J., Yu, G., Barra, A., Wang, K.L., and Carman, G.P., Strain-mediated spin-orbit torque switching for magnetic memory, arXiv Preprint, 2017.