Joint Seminar by IEEE Magnetics Society and ECE Department - Magnetic Memory Driven by Topological Insulators
Reducing the energy consumption is one of the major challenges for next-generation spintronic devices. Spin-momentum locking in topological surface states gives rise to a giant spin-orbit torque (SOT) efficiency, and thus to reduce the writing energy of SOT devices. By combing the topological insulators (TIs) with in-plane magnetic tunnel junctions (MTJs), we demonstrate the proof-of-concept SOT-MRAM cell, where a large TMR ratio of 102% and the ultralow switching current density of 1.2 × 105 A cm−2 have been simultaneously achieved at room temperature. The charge-spin conversion efficiency θSH is characterized by the switching field shift and the spin-torque ferromagnetic resonance (ST-FMR) methods, and the >1 θSH proves the high efficiency of topological surface states. Moreover, the all-sputtered TI-MTJ device is demonstrated, showing the potential for wafer-scale industrial applications. Next, by combing the TIs with perpendicular MTJs, we realize the all-electrical low-power writing operation by combing the SOT with a small spin-transfer torque current, with the improving thermal stability and storage density. Our work proposes and demonstrates the magnetic memory driven by topological insulators, which may inspire the revolution of spintronic devices from classical to quantum materials.
Dr. Hao Wu graduated from Lanzhou University in 2012 and obtained his PhD degree from the Institute of Physics, Chinese Academy of Sciences in 2017, and then worked as a postdoctoral researcher in the area of spintronics at the University of California, Los Angeles (UCLA) in the United States, during 2017 ~ 2021. Since 2021, Dr. Hao Wu has been working at the Songshan Lake Materials Laboratory, and was the head of the Spintronic Quantum Materials and Devices group. He was a recipient of the National Overseas High-Level Young Talents Program. He has published more than 90 SCI papers in peer-reviewed journals such as Nature Electronics/Communications, Physical Review Letters, Advanced Materials, etc. with more than 3000 citations. He has presented at over 10 international academic conferences. He serves as the Editor of Materials Futures, Materials, and so on. He has been honored with the Young Scientist Medal by the International Association of Advanced Materials