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摘要翻译：
在磁系统的数值模拟中，已观察到交变磁场与周期P有关的动态相变(DPT)。然而，在磁滞回线面积标度研究中，这种DPT的实验证据迄今仅限于磁滞回线塌陷的定性观察。在具有强垂直各向异性的[Co(4a)/Pt(7a)]_3-多层体系中，我们为这种DPT的实验观察提供了更有力的证据。我们在[Co/Pt]3多层膜上施加了一个平面外时变（锯齿）场，外加一个小的常数场H_b。然后，我们测量得到的平面外磁化时间序列，以产生循环平均磁化强度Q及其方差Var(Q)作为P和H_b的函数的非平衡相图。实验结果与Ising动力学模型在类似条件下的计算结果非常相似。实验和模拟的NEPDs的相似性，特别是实验结果中方差Var(Q)中存在一个局域峰，构成了在我们的磁多层样品中存在这种DPT的有力证据。与用于产生时变外加场的电磁铁的迟滞性质和响应时间相关的技术挑战阻止了我们从当前数据中提取有意义的临界标度指数。然而，基于我们的结果，我们提出了对实验过程的改进，这可能使未来的临界指数的确定成为可能。
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英文标题：
《Evidence for a dynamic phase transition in [Co/Pt]_3 magnetic
multilayers》
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作者：
D. T. Robb, Y. H. Xu, O. Hellwig, J. McCord, A. Berger, M. A. Novotny,
and P. A. Rikvold
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最新提交年份：
2008
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分类信息：
一级分类：Physics 物理学
二级分类：Statistical Mechanics 统计力学
分类描述：Phase transitions, thermodynamics, field theory, non-equilibrium phenomena, renormalization group and scaling, integrable models, turbulence
相变，热力学，场论，非平衡现象，重整化群和标度，可积模型，湍流
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一级分类：Physics 物理学
二级分类：Materials Science 材料科学
分类描述：Techniques, synthesis, characterization, structure. Structural phase transitions, mechanical properties, phonons. Defects, adsorbates, interfaces
技术，合成，表征，结构。结构相变，力学性质，声子。缺陷，吸附质，界面
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英文摘要：
A dynamic phase transition (DPT) with respect to the period P of an applied alternating magnetic field has been observed previously in numerical simulations of magnetic systems. However, experimental evidence for this DPT has thus far been limited to qualitative observations of hysteresis loop collapse in studies of hysteresis loop area scaling. Here, we present significantly stronger evidence for the experimental observation of this DPT, in a [Co(4 A)/Pt(7 A)]_3-multilayer system with strong perpendicular anisotropy. We applied an out-of-plane, time-varying (sawtooth) field to the [Co/Pt]_3 multilayer, in the presence of a small additional constant field, H_b. We then measured the resulting out-of-plane magnetization time series to produce nonequilibrium phase diagrams (NEPDs) of the cycle-averaged magnetization, Q, and its variance, Var(Q), as functions of P and H_b. The experimental NEPDs are found to strongly resemble those calculated from simulations of a kinetic Ising model under analagous conditions. The similarity of the experimental and simulated NEPDs, in particular the presence of a localized peak in the variance Var(Q) in the experimental results, constitutes strong evidence for the presence of this DPT in our magnetic multilayer samples. Technical challenges related to the hysteretic nature and response time of the electromagnet used to generate the time-varying applied field precluded us from extracting meaningful critical scaling exponents from the current data. However, based on our results, we propose refinements to the experimental procedure which could potentially enable the determination of critical exponents in the future.
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PDF链接：
https://arxiv.org/pdf/708.0051
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