Phase locking experiments on vortex based spin transfer oscillators with anexternal microwave current are performed. We present clear evidence of phaselocking, frequency pulling, as well as fractional synchronization in thissystem, with a minimum peak linewidth of only 3 kHz in the locked state. Wefind that locking ranges of the order of 1/3 of the oscillator frequency areeasily achievable because of the large tunability $\partial f/\partial I_{dc}$observed in our vortex based systems. Such large locking ranges allow us todemonstrate the simultaneous phase locking of two independent oscillatorsconnected in series with the external source.
展开▼
