We report the magnetization dynamics and the magnetization switching mechanism under spin wave excitation in exchange-coupled bilayers. The in-plane magnetized L10-FePt and Ni81Fe19 (permalloy; Py) layers were exchange-coupled through the interface, and the spatially twisted magnetic structure was formed when the external magnetic field was applied owing to the difference in the switching fields (H sw) between L10-FePt and Py. The ferromagnetic resonance spectra for the microfabricated bilayer element indicated that several kinds of quantized spin wave modes existed. Among the quantized spin wave modes, the perpendicular standing spin wave (PSSW) modes were amplified remarkably when the magnetization dynamics were largely excited by applying the external rf magnetic field (H rf). Consequently, the microfabricated bilayer element showed clear H sw reduction due to the assistance of PSSW. In addition, narrow H sw distribution was observed for the spin wave-assisted magnetization switching. We examined the characteristic tendency of spin wave-assisted magnetization switching using pulse-like H rf application measurement, and found that the resonant magnetization switching was mainly induced in the conditions exciting the PSSW modes but unexpected off-resonant switching also appeared at the high magnetic field.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Acoustics and Ultrasonics
- Surfaces, Coatings and Films