Spin-Wave Modes in Exchange-Coupled FePt/FeNi Bilayer Films
LI Shu-Fa1**, HE Pan2, CHENG Chu-Yuan1, ZHOU Shi-Ming2**, LAI Tian-Shu1**
1State-Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 2Department of Physics, Tongji University, Shanghai 200092
Abstract：A simple magnetic modulation structure of the exchange-coupling FePt/FeNi bilayer film is fabricated and studied for its magnetization dynamics using time-resolved magneto-optical polar Kerr spectroscopy. It is found that two spin-wave modes can be excited. One is fixed at ～3.2 GHz in frequency for any external field and may serve as a frequency-stabilized spin-wave filter, while the other is external field dependent. In contrast, only the external field-dependent mode is excited in single-layer FeNi, supporting the localized origin of the mode at ～3.2 GHz, which is confined to a thin exchange-coupling region. The other external field-dependent mode in frequency is attributed to the Kittel mode.
2014, Vol. 31 
