Abstract: In this paper, we introduce how the frequency-modulated microwave used in the experiment of ferromagnetio resonance. In our experiment, the resonant frequency of the transmission resonant cavity can be measured rapidly by using the frequency-modulated microwave emitted from the klystron. Then, by means of mechanical and electronic tuning, it is very convenient to make the frequency of the microwave resonating with that of the cavity. Based on the former adjusting, the resonant curve of the ferromagnetic single-crystalline materials can be easily obtained.

Key words: frequency-modulated microwave, ferromagnetic resonance, transmission resonant cavity