Fachbereich Physik and Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
Phys Rev Lett. 2009 Oct 9;103(15):157202. doi: 10.1103/PhysRevLett.103.157202. Epub 2009 Oct 8.
We have investigated the generation of spin waves in the free layer of an extended spin-valve structure with a nanoscaled point contact driven by both microwave and direct electric current using Brillouin light scattering microscopy. Simultaneously with the directly excited spin waves, strong nonlinear effects are observed, namely, the generation of eigenmodes with integer multiple frequencies (2f, 3f, 4f) and modes with noninteger factors (0.5f, 1.5f) with respect to the excitation frequency f. The origin of these nonlinear modes is traced back to three-magnon-scattering processes. The direct current influence on the generation of the fundamental mode at frequency f is related to the spin-transfer torque, while the efficiency of three-magnon-scattering processes is controlled by the Oersted field as an additional effect of the direct current.
我们通过使用布里渊光散射显微镜研究了在由微波和直流电流驱动的纳米点接触扩展自旋阀结构的自由层中自旋波的产生。除了直接激发的自旋波之外，还观察到了强烈的非线性效应，即在激发频率 f 的整数倍频率（2f、3f、4f）和非整数倍频率（0.5f、1.5f）下产生本征模。这些非线性模式的起源可以追溯到三磁振子散射过程。直流电流对频率为 f 的基本模式的产生的影响与自旋转移力矩有关，而三磁振子散射过程的效率则由奥斯特场控制，这是直流电流的附加效应。
