AI 中文总结
研究自旋电子二极管中分数参量共振问题，基于微磁模拟和解析模型分析，发现交流自旋转移力矩与电压控制磁各向异性共同作用下出现分数频率共振，为非线性信号处理和电磁能量收集应用开辟新方向。
AI 中文摘要
参量泵浦是激发、放大和处理不同性质振荡和波的有力工具。一般来说，当泵浦频率\(f_p\)与线性模式（或波）的本征频率\(f_0\)满足\(f_p = 2f_0/n\)（\(n = 1,2,3,\cdots\)）时会发生参量共振。在机械、超导和量子系统中这种共振很常见，但在磁性和自旋电子系统中，仅研究了最低（\(n = 1\)）的参量共振。本文通过基于微磁模拟和解析模型的理论分析，表明在交流自旋转移力矩和电压控制磁各向异性共同作用下的自旋电子二极管中出现了分数频率（\(f_p = 2f_0/n\)，\(n>10\)）的共振。解析模型表明参量磁化动力学不能简化为参量振荡器的标准马蒂厄模型，证明了电压控制磁各向异性驱动的模式频率调制的关键作用，它与参量耦合一起导致了高阶奇数（\(n = 3,5,7,\cdots\)）分数共振，而与线性自旋转移力矩驱动同时作用会产生无阈值偶数（\(n = 4,6,8,\cdots\)）共振。这种高阶参量动力学不仅限于电压控制磁各向异性泵浦，为自旋电子二极管在非线性信号处理和电磁能量收集方面的应用开辟了新方向。
英文摘要
Parametric pumping is a powerful tool for the excitation, amplification, and processing of oscillations and waves of different nature. In general, parametric resonance can occur when the pumping frequency $f_p$ and eigenfrequency of a linear mode (or wave) $f_0$ satisfy the relation $f_p$=2$f_0$/n (n=1,2,3,...). While such parametric resonance is well known in mechanical, superconductive, and quantum systems, in magnetic and spintronic systems only the lowest (n=1) parametric resonance at double the spin wave mode frequency $f_p$=2$f_0$ was thoroughly studied and explored. Here, using a theoretical analysis based on both micromagnetic simulations and an analytical model, we show the emergence of resonances at fractional frequencies $f_p$=2$f_0$/n (with n>10) in spintronic diodes driven by the simultaneous action of ac spin-transfer torque (STT, current densities < $10^6$ A/cm2) and voltage-controlled magnetic anisotropy (VCMA, effective anisotropy fields < 50 mT). The analytical model shows that parametric magnetization dynamics is irreducible to the standard Mathieu model of a parametric oscillator and demonstrates the crucial role of VCMA-driven mode frequency modulation: together with parametric coupling, it results in higher-order odd (n=3,5,7,...) fractional resonances, observed above certain VCMA pumping threshold, while simultaneous action with linear STT drive produces thresholdless even (n=4,6,8,...) resonances. This higher-order parametric dynamics is not restricted to VCMA pumping and opens new directions for the application of spintronic diodes for nonlinear signal processing and electromagnetic energy harvesting.
