Enhanced Modulation Bandwidth of a Magnetic Tunnel Junction-Based Spin Torque Nano-Oscillator Under Strong Current Modulation

The modulation bandwidth (
${f}_{{BW}}$
) is a critical figure-of-merit for wireless communication applications of spin torque nano-oscillators (STNOs) as it determines the maximum data rate. Although both theory and previous experiments have shown that
${f}_{{BW}}$
in STNOs is governed by the amplitude relaxation frequency
${f}_{{\mathrm {p}}}$
, we here demonstrate, using single-shot time-resolved measurements of a magnetic tunnel junction based STNO, that it can be many times larger under strong modulation. The behavior is qualitatively reproduced in macrospin simulations. Our results show that
${f}_{{BW}}$
of STNOs is not as limiting a factor for future wireless applications as previously believed.