Efficient Excitation of High-Frequency Exchange-Dominated Spin Waves in Periodic Ferromagnetic Structures
- Univ. of California, Los Angeles, CA (United States)
- Univ. of California, Riverside, CA (United States)
Spin waves are of great interest as an emerging solution for computing beyond the limitations of scaled transistor technology. In such applications, the frequency of the spin waves is important as it affects the overall frequency performance of the resulting devices. In conventional ferromagnetic thin films, the magnetization dynamics in ferromagnetic resonance and spin waves are limited by the saturation magnetization of the ferromagnetic (FM) material and the external bias field. High-frequency applications would require high external magnetic fields which limit the practicality in a realistic device. One solution is to couple microwave excitations to perpendicular standing spin waves (PSSWs) which can enable higher oscillation frequencies. However, efficient coupling to these modes remains a challenge since it requires an excitation that is nonuniform across the FM material thickness and current methods have proven to be inefficient, resulting in weak excitations. Here, we show that by creating periodic undulations in a 100-nm-thick Co40Fe40B20 layer, high-frequency PSSWs (>20 GHz) can be efficiently excited using micrometer-sized transducers at bias fields below 100 Oe which absorb nearly 10% of the input rf power. We suggest efficient excitation of such spin waves at low fields may enable high-frequency spintronic applications using exchange-dominated magnetic oscillations using very low external magnetic fields and, with design optimizations, can bring about alternative possibilities in the field.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Spins and Heat in Nanoscale Electronic Systems (SHINES); Univ. of California, Riverside, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- Grant/Contract Number:
- SC0012670; EFRI-1433541; EEC-1160504
- OSTI ID:
- 1470342
- Journal Information:
- Physical Review Applied, Vol. 7, Issue 3; Related Information: SHINES partners with University of California, Riverside (lead); Arizona State University; Colorado State University; Johns Hopkins University; University of California Irvine; University of California Los Angeles; University of Texas at Austin; ISSN 2331-7019
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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