论文标题
超纳秒旋转转移扭矩在超磁性纳米磁体的合奏中
Sub-Nanosecond Spin-Transfer Torque in an Ensemble of Superparamagnetic-Like Nanomagnets
论文作者
论文摘要
自旋电流即使在消失的小净磁化极限，也可以在磁系统上施加自旋转移扭矩，就像抗铁磁铁一样。在这里，我们通过实验表明，自旋转移扭矩是在具有弱，短磁极序列的材料中可操作的 - 即，超帕磁性的CO纳米磁体的宏观集合。我们采用元素和时间分辨的X射线铁磁共振（XFMR）光谱直接检测CO纳米磁体的子NS动力学，通过振荡自旋电流激发了用锥角$ \ geq $ 0.003 $ 0.003 $ 0.003 $^{\ geq $ 0.003 $ 0.003 $^{\ circ} $激发。 XFMR测量结果表明，随着整体的净力矩减小，相对于磁场扭矩的旋转扭矩的强度会增加。我们的发现指出自旋转移扭矩是操纵子NS时标的纳米磁体团体状态的有效方法。
Spin currents can exert spin-transfer torques on magnetic systems even in the limit of vanishingly small net magnetization, as is the case for antiferromagnets. Here, we experimentally show that a spin-transfer torque is operative in a material with weak, short-range magnetic order -- namely, a macroscopic ensemble of superparamagnetic-like Co nanomagnets. We employ element- and time-resolved X-ray ferromagnetic resonance (XFMR) spectroscopy to directly detect sub-ns dynamics of the Co nanomagnets, excited into precession with cone angle $\geq$0.003$^{\circ}$ by an oscillating spin current. XFMR measurements reveal that as the net moment of the ensemble decreases, the strength of the spin-transfer torque increases relative to those of magnetic field torques. Our findings point to spin-transfer torque as an effective way to manipulate the state of nanomagnet ensembles at sub-ns timescales.
