Element-Specific Detection of Sub-Nanosecond Spin-Transfer Torque in a Nanomagnet Ensemble.
Element-Specific Detection of Sub-Nanosecond Spin-Transfer Torque in a Nanomagnet Ensemble.
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DOI：
10.1021/acs.nanolett.0c01868
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发表时间：
2020-05
期刊：
影响因子：
10.8
通讯作者：
S. Emori;C. Klewe;J. Schmalhorst;Jan Krieft;P. Shafer;Youngmin Lim;David A. Smith;A. Sapkota;A. Srivastava;C. Mewes;Zijian Jiang;B. Khodadadi;Hesham Elmkharram;J. Heremans;E. Arenholz;Günter Reiss;T. Mewes
中科院分区：
文献类型：
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作者：
S. Emori;C. Klewe;J. Schmalhorst;Jan Krieft;P. Shafer;Youngmin Lim;David A. Smith;A. Sapkota;A. Srivastava;C. Mewes;Zijian Jiang;B. Khodadadi;Hesham Elmkharram;J. Heremans;E. Arenholz;Günter Reiss;T. Mewes
自旋电流可以对磁性系统施加自旋转移力矩，即使在极小的净磁化强度的极限下也是如此，正如最近对反铁磁体所显示的那样。在这里，我们的实验表明，自旋转移力矩是在弱相互作用，随机磁化的Co纳米磁体的宏观系综。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纳米磁体的亚纳秒动力学，通过振荡自旋电流激发进入旋进，锥角为<$0.003 °。XFMR测量结果表明，作为合奏的净力矩的减少，自旋转移扭矩的强度增加相对于那些磁场扭矩。我们的研究结果指出，自旋转移力矩作为一种有效的方式来操纵状态的纳米磁体合奏在亚纳秒的时间尺度。
Spin currents can exert spin-transfer torques on magnetic systems even in the limit of vanishingly small net magnetization, as recently shown for antiferromagnets. Here, we experimentally show that a spin-transfer torque is operative in a macroscopic ensemble of weakly interacting, randomly magnetized Co nanomagnets. We employ element- and time-resolved X-ray ferromagnetic resonance (XFMR) spectroscopy to directly detect subnanosecond dynamics of the Co nanomagnets, excited into precession with cone angle ≳0.003° 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 subnanosecond time scales.