Modulation rate study in spin torque oscillator based wireless communication system

Wireless transmission requires a circuitry to generate GHz range signal. Spin transfer torque devices are one of the promising candidates for generating stable signal in the GHz range through collective precession of the local spins in one of the ferromagnetic layer, known as free layer. Another ferromagnetic layer, fixed layer, acts as a medium to convert the incoming electric current into spin polarized current. This spin polarized current drives local spins of the free layer into constant precession. Factors like high linewidth, low output power and modulation rate are yet to be optimized to make these devices ready for use in practical wireless communication system. Recently, H. S. Choi et al. , has demonstrated the first ever complete wireless communication system using spin torque nano-oscillators (STNOs) through the amplitude shift keying (ASK) modulation. Here, we present a more detailed study of wireless communication as a function of the modulation frequency and distance between receiver and transmitting antennas (T_x) in order to determine modulation rate limits.