The damping of spin waves parametrically excited in the magnetic insulatorYttrium Iron Garnet (YIG) is controlled by a dc current passed through anadjacent normal-metal film. The experiment is performed on a macroscopicallysized YIG(100nm)/Pt(10nm) bilayer of 4x2 mm^2 lateral dimensions. The spin-waverelaxation frequency is determined via the threshold of the parametricinstability measured by Brillouin light scattering (BLS) spectroscopy. Theapplication of a dc current to the Pt film leads to the formation of aspin-polarized electron current normal to the film plane due to the spin Halleffect (SHE). This spin current exerts a spin transfer torque (STT) in the YIGfilm and, thus, changes the spin-wave damping. Depending on the polarity of theapplied dc current with respect to the magnetization direction, the damping canbe increased or decreased. The magnitude of its variation is proportional tothe applied current. A variation in the relaxation frequency of +/-7.5% isachieved for an applied dc current density of 5*10^10 A/m^2.
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机译：在磁性绝缘子中参数化激发的自旋波的阻尼由流过相邻正常金属膜的直流电流控制。实验是在横向尺寸为4x2 mm ^ 2的宏观尺寸的YIG（100nm）/ Pt（10nm）双层上进行的。自旋波弛豫频率是通过布里渊光散射（BLS）光谱法测量的参数不稳定性阈值确定的。由于自旋霍尔效应（SHE），向Pt膜施加直流电流会导致形成垂直于膜平面的Aspin极化电子电流。该自旋电流在YIGfilm中施加自旋传递扭矩（STT），从而改变自旋波阻尼。根据所施加的直流电流相对于磁化方向的极性，可以增加或减小阻尼。其变化幅度与施加的电流成正比。对于5 * 10 ^ 10 A / m ^ 2施加的直流电流密度，可以实现+/- 7.5％的弛豫频率变化。
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