Wide-range control of ferromagnetic resonance by spin Hall effect

We demonstrate experimentally that the characteristics of the ferromagnetic resonance in a microscopic magnetic system based on a Permalloy/Cu/Pt multilayer can be varied over a wide range by the spin Hall effect. Specifically, by applying a dc current through the Pt strip, we achieve a reduction of the effective damping constant in Permalloy by a factor of two below its standard value. We show that this reduction is not significantly affected by the Joule heating effects. We also find that, apart from influencing the damping, the spin Hall effect results in the amplification or suppression of the coherent magnetization dynamics.

[1]  T. Miyazaki,et al.  Effect of spin diffusion on Gilbert damping for a very thin permalloy layer in Cu/permalloy/Cu/Pt films , 2002 .

[2]  D. Ralph,et al.  Microwave oscillations of a nanomagnet driven by a spin-polarized current , 2003, Nature.

[3]  D. Ralph,et al.  Spin-transfer-driven ferromagnetic resonance of individual nanomagnets. , 2006, Physical review letters.

[4]  J. Hirsch.  Spin Hall Effect , 1999, cond-mat/9906160.

[5]  C. Kittel.  On the Theory of Ferromagnetic Resonance Absorption , 1948 .

[6]  S. Maekawa,et al.  Electric manipulation of spin relaxation using the spin Hall effect. , 2008, Physical review letters.

[7]  D. Ralph,et al.  Time-Domain Measurements of Nanomagnet Dynamics Driven by Spin-Transfer Torques , 2005, Science.

[8]  V. Demidov,et al.  Micro-Brillouin Light Scattering Spectroscopy of Magnetic Nanostructures , 2008, IEEE Transactions on Magnetics.

[9]  M D Stiles,et al.  Control of magnetic fluctuations by spin current. , 2011, Physical review letters.

[10]  Sergei Urazhdin,et al.  Direct observation and mapping of spin waves emitted by spin-torque nano-oscillators. , 2010, Nature materials.

[11]  S. Urazhdin,et al.  Control of spin-wave emission from spin-torque nano-oscillators by microwave pumping , 2011 .

[12]  J. Katine,et al.  Mutual phase-locking of microwave spin torque nano-oscillators , 2005, Nature.

[13]  A. Fert,et al.  Large microwave generation from current-driven magnetic vortex oscillators in magnetic tunnel junctions. , 2010, Nature communications.

[14]  D. Ralph,et al.  Spin-torque ferromagnetic resonance induced by the spin Hall effect. , 2010, Physical review letters.

[15]  B. N. Engel,et al.  Phase-locking in double-point-contact spin-transfer devices , 2005, Nature.

[16]  S. Yuasa,et al.  Spin-torque diode effect in magnetic tunnel junctions , 2005, Nature.

[17]  Xiao Cheng,et al.  Nonadiabatic stochastic resonance of a nanomagnet excited by spin torque. , 2010, Physical review letters.