Thermally Assisted Current-Driven Dynamics in Asymmetric Spin Valves
M. Gmitra a, b, J. Barnaś c and D. Horváth a
a Department of Theoretical Physics and Astrophysics, P.J.Šafárik University, Park Angelinum 9, 040 01 Košice, Slovak Republic
b Inst. for Theor. Physics, University of Regensburg, 93040 Regensburg, Germany
c Department of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
and
Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland
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Received: 9 07 2007;
Current-induced steady precessional modes in standard spin valves are usually excited as an interplay of spin-transfer torque, Gilbert damping, and external magnetic field. We propose an asymmetric spin valve, in which the spin current can excite stationary precessional modes also at zero external magnetic field. We also show that finite temperature can induce transitions between different dynamical modes. These transitions, in turn, lead to telegraph noise in magnetoresistance.
DOI: 10.12693/APhysPolA.113.31
PACS numbers: 75.60.Ch, 75.70.Cn