Low-power nonvolatile spintronics offers the potential for green electronic systems with zero standby power, resulting in a transformative potential for the whole electronics industry. By dramatically reducing power consumption compared to scaled CMOS, spintronics can have game-changing effects in the emerging era of Internet of Things, as well as in intelligent systems and computing solutions beyond scaled CMOS. In this project we focus on developing voltage- and current-controlled magnetic devices with superior energy efficiency and scalability for green electronics, with applications to memory and logic elements.
Challenges: The challenges in developing low-power spintronic devices based on spin-orbit engineering include: (i) experimental control to the atomic level of interfaces, thicknesses, and compositions of magnetic and non-magnetic layers, which in turn affect their spin transport and magnetoelectric properties, and (ii) theoretical understanding of the effects of materials choices and layer stack engineering, including spin-orbit interaction, band structure, and lateral confinements, on the magnetization dynamics and device behaviour.
Objectives: The focus of this project is on engineering of spin-orbit interaction at interfaces, resulting in large voltage- and current-induced torques on the magnetization, which are applicable to memory, logic, and microwave devices. Based on the innovative material systems developed, we then demonstrate devices utilizing there spin-orbit effects and assess their performance in terms of energy, speed, and other relevant metrics for use in practical systems.
Approach: We employ state of the art experimental facilities and theoretical techniques to address the challenges in this project. Material stacks are developed using a two-chamber dedicated magnetron sputtering system with capability of depositing up to 11 different materials without breaking vacuum. Device fabrication is performed at UCLA and CNSI’s state of the art facilities, which include e-beam patterning down to below 20 nm in lateral width, while device measurements are performed on our dedicated probe stations with magnetic field and temperature control capability, allowing for testing from DC up to 40 GHz frequencies. To enhance theoretical understanding, we also employ first principles calculations as well as micromagnetic simulations using both commercial and in-house developed codes.