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Magnetization Dynamics Driven by Spin Currents in Magnetic Hybrid Structures

February 12, 2013 11:00AM to 12:00PM
Presenter 
Antonio Azevedo, Universidade Federal de Pernambuco
Location 
Building 223, Room S105
Type 
Seminar
Series 
Materials Science Seminar
Abstract:
In this talk, I will review various recent experimental achievements [1] relevant for understanding how spin current generated by different schemes interacts with spin waves in magnetic hybrid structures. By using spin current generated by both spin pumping and spin thermal effects it has been made possible to interact with spin waves either amplifying or attenuating its amplitude. One of the most surprising effects is the amplification of propagating spin waves pulses in single crystal yttrium iron garnet (YIG) films under action of a thermal gradient. In this case the temperature gradient can be used to control the relaxation rate of spin-wave packets propagating along the film of YIG covered by a very thin Pt layer.

The change in the relaxation rate is attributed to the action of a spin current generated through the spin Seebeck effect that depending on its direction can enhance or diminish the spin pumping damping due to the contact of the Pt layer with the YIG film. We also explore how the spin pumping effect occurring at ferromagnetic/non-magnetic interfaces, can cause a ferromagnetic resonance (FMR) line broadening in thick YIG slabs. The relaxation of the transversal component of the magnetization must be relevant in order to explain some puzzling results obtained by FMR.

References:
[1] Physical Review Letters, 107, 197203 (2011); Applied Physics Letters, 102 (1), 012401 (2013); Applied Physics Letters, 99, 192511 (2011).