Autonomous and forced dynamics in a spin-transfer nano-oscillator: Quantitative magnetic-resonance force microscopy
Autonomous and forced dynamics in a spin-transfer nano-oscillator: Quantitative magnetic-resonance force microscopy
复制标题
自旋转移纳米振荡器中的自主和受迫动力学：定量磁共振力显微镜
DOI：
10.1103/physrevb.85.140408
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发表时间：
2012
影响因子：
3.7
通讯作者：
O. Klein
中科院分区：
文献类型：
--
作者：
A. Hamadeh;G. D. Loubens;V. Naletov;J. Grollier;C. Ulysse;V. Cros;O. Klein
使用磁共振力显微镜 (MRFM)，在自主和强制状态下测量由正常磁化的 Py$|$Cu$|$Py 圆形纳米柱组成的自旋转移纳米振荡器发出的功率。根据自主动力学亚临界区域的功率行为，可以获得阈值电流和噪声水平的定量测量。它们的场依赖性直接产生作用于薄层的自旋扭矩效率和首先自动振荡的模式的性质：能量最低、空间上最均匀的自旋波模式。从强制动力学中的 MRFM 行为，可以证明，为了锁相这种自振荡模式，外部源必须具有与模式轮廓相同的空间对称性，即必须使用均匀的微波场，而不是流过纳米柱的微波电流。
Using a magnetic resonance force microscope (MRFM), the power emitted by a spin transfer nano-oscillator consisting of a normally magnetized Py$|$Cu$|$Py circular nanopillar is measured both in the autonomous and forced regimes. From the power behavior in the subcritical region of the autonomous dynamics, one obtains a quantitative measurement of the threshold current and of the noise level. Their field dependence directly yields both the spin torque efficiency acting on the thin layer and the nature of the mode which first auto-oscillates: the lowest energy, spatially most uniform spin-wave mode. From the MRFM behavior in the forced dynamics, it is then demonstrated that in order to phase-lock this auto-oscillating mode, the external source must have the same spatial symmetry as the mode profile, \textit{i.e.}, a uniform microwave field must be used rather than a microwave current flowing through the nanopillar.