Strong linewidth variation for spin-torque nano-oscillators as a   function of in-plane magnetic field angle
  We measure the microwave signals produced by spin-torque-driven magnetization dynamics in patterned magnetic multilayer devices at room temperature, as a function of the angle of a magnetic field applied in the sample plane. We find strong variations in the frequency linewidth of the signals, with a decrease by more than a factor of 20 as the field is rotated from the magnetic easy axis to the in-plane hard axis. Based on micromagnetic simulations, we identify these variations as due to a transition from spatially incoherent to coherent precession. 
K.V. Thadani, G. Finocchio, Z.-P. Li, O. Ozatay, J.C. Sankey, I.N.   Krivorotov, Y.-T. Cui, R.A. Buhrman, D.C. Ralph