Jiang Sheng, Chung Sunjae, Le Quang Tuan, Wong Ping Kwan Johnny, Zhang Wen, Åkerman Johan
School of Microelectronics, South China University of Technology, 510641 Guangzhou, China.
Department of Physics, University of Gothenburg, 41296 Gothenburg, Sweden.
Nano Lett. 2023 Feb 22;23(4):1159-1166. doi: 10.1021/acs.nanolett.2c03613. Epub 2023 Feb 7.
Spin-torque nano-oscillators (STNOs) are a type of nanoscale microwave auto-oscillators utilizing spin-torque to generate magnetodynamics with great promise for applications in microwaves, magnetic memory, and neuromorphic computing. Here, we report the first demonstration of exchange-spring STNOs, with an exchange-spring ([Co/Pd]-Co) reference layer and a perpendicular ([Co/Ni]) free layer. This magnetic configuration results in high-frequency (>10 GHz) microwave emission at a zero magnetic field and exchange-spring dynamics in the reference layer and the observation of magnetic droplet solitons in the free layer at different current polarities. Our demonstration of bipolar and field-free exchange-spring-based STNOs operating over a 20 GHz frequency range greatly extends the design freedom and functionality of the current STNO technology for energy-efficient high-frequency spintronic and neuromorphic applications.
自旋扭矩纳米振荡器（STNO）是一种纳米级微波自激振荡器，利用自旋扭矩产生磁动力学，在微波、磁存储器和神经形态计算等应用中具有巨大潜力。在此，我们首次展示了交换弹簧STNO，它具有一个交换弹簧（[Co/Pd]-Co）参考层和一个垂直（[Co/Ni]）自由层。这种磁结构在零磁场下产生高频（>10 GHz）微波发射，参考层呈现交换弹簧动力学，并且在自由层中观察到不同电流极性下的磁滴孤子。我们展示的基于交换弹簧的双极无场STNO在20 GHz频率范围内工作，极大地扩展了当前STNO技术在节能高频自旋电子学和神经形态应用中的设计自由度和功能。
