Tunable Optical Mode Ferromagnetic Resonance in FeCoB/Ru/FeCoB Synthetic Antiferromagnetic Trilayers under Uniaxial Magnetic Anisotropy |
| |
| Authors: | Shandong Li Qiang Li Jie Xu Shishen Yan Guo‐Xing Miao Shishou Kang Youyong Dai Jiqing Jiao Yueguang Lü |
| |
| Affiliation: | 1. College of Physics, Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, and Key Laboratory of Photonics Materials and Technology in Universities of Shandong, Qingdao University, Qingdao, P.R. China;2. National Laboratory of Solid State Microstructures, Nanjing University, Nanjing, P.R. China;3. Department of Electrical and Computer Engineering, Institute for Quantum Computing, University of Waterloo, Waterloo, Canada;4. School of Physics, Shandong University, Jinan, P.R. China;5. Collaborative Innovation Center for Low‐Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao, P.R. China;6. School of Chemical Science and Engineering, Qingdao University, Qingdao, P.R. China;7. Department of Physics, School of Science, Harbin Institute of Technology, Harbin, P.R. China |
| |
| Abstract: | Ferromagnetic resonance (FMR) is one of the most important characteristics of soft magnetic materials, which practically sets the maximum operation speed of these materials. There are two FMR modes in exchange coupled ferromagnet/nonmagnet/ferromagnet sandwich films. The acoustic mode has relatively lower frequency and is widely used in radio‐frequency/microwave devices, while the optical mode is largely neglected due to its tiny permeability even though it supports much higher frequency. Here, a realistic method is reported to enhance the permeability in the optical mode to an applicable level. FeCoB/Ru/FeCoB trilayers are carefully engineered with both uniaxial magnetic anisotropy and antiferromagnetic interlayer exchange coupling. This special magnetic structure exhibits a high optical mode frequency up to 11.28 GHz and a maximum permeability of 200 at resonance. An abnormally low inverse switch field (<200 Oe, less than 1/5 of the single layer) is observed which can effectively switch the system from optical mode with higher frequency into acoustic mode with lower frequency. The optical mode frequency and inverse switch field can be controlled by tailoring the interlayer coupling strengths and the uniaxial anisotropy fields, respectively. The tunable optical mode resonance thus can increase operation frequency while reduce operation field overhead in FMR based devices. |
| |
| Keywords: | composition gradient sputtering electric field tunability magnetoelectric coupling microwave ferromagnetic films multiferroic |
|
|
