Spin-Torque Diode Measurements of MgO-Based Magnetic Tunnel Junctions   with Asymmetric Electrodes
  We present a detailed study of the spin-torque diode effect in CoFeB/MgO/CoFe/NiFe magnetic tunnel junctions. From the evolution of the resonance frequency with magnetic field at different angles, we clearly identify the free-layer mode and find an excellent agreement with simulations by taking into account several terms for magnetic anisotropy. Moreover, we demonstrate the large contribution of the out-of-plane torque in our junctions with asymmetric electrodes compared to the in-plane torque. Consequently, we provide a way to enhance the sensitivity of these devices for the detection of microwave frequency. 
R. Matsumoto, A. Chanthbouala, J. Grollier, V. Cros, A. Fert, K.   Nishimura, Y. Nagamine, H. Maehara, K. Tsunekawa, A. Fuku...
cond-mat.mtrl-sci