Temperature dependence of microwave voltage emission associated to   spin-transfer induced vortex oscillation in magnetic tunnel junction
  The temperature dependence of a vortex-based nano-oscillator induced by spin transfer torque (STVO) in magnetic tunnel junctions (MTJ) is considered. We obtain emitted signals with large output power and good signal coherence. Due to the reduced non-linearities compared to the uniform magnetization case, we first observe a linear decrease of linewidth with decreasing temperature. However, this expected behavior no longer applies at lower temperature and a bottom limit of the linewidth is measured. 
P. Bortolotti, A. Dussaux, J. Grollier, V. Cros, A. Fukushima, H.   Kubota, K. Yakushiji, S. Yuasa, K. Ando, and A. Fert
cond-mat.mtrl-sci