...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physical review >Nonwhite frequency noise in spin torque oscillators and its effect on spectral linewidth
【24h】

Nonwhite frequency noise in spin torque oscillators and its effect on spectral linewidth

机译：自旋扭矩振荡器中的非白频噪声及其对谱线宽的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We measure the power spectral density of frequency fluctuations in nanocontact spin torque oscillators over time scales up to 50 ms. We use a mixer to convert oscillator signals ranging from 10 GHz to 40 GHz into a band near 70 MHz before digitizing the time-domain waveform. We analyze the waveform using both zero crossing time stamps and a sliding Fourier transform, discuss the different limitations and advantages of these two methods, and combine them to obtain a frequency noise spectrum spanning more than five decades of Fourier frequency f. For devices having a free layer consisting of either a single Ni_(80)Fe_(20) layer or a Co/Ni multilayer we find a frequency noise spectrum that is white at large f and varies as 1 /f at small f. The crossover frequency ranges from ≈10~4 Hz to ≈10~6 Hz and the 1/fcomponent is stronger in the multilayer devices. Through actual and simulated spectrum analyzer measurements, we show that 1/f frequency noise causes both broadening and a change in shape of the oscillator's spectral line as measurement time increases. Our results indicate that the long term stability of spin torque oscillators cannot be accurately predicted from models based on thermal (white) noise sources.
机译：我们测量了纳米接触自旋转矩振荡器中频率波动的功率谱密度，其时间尺度长达50 ms。在将时域波形数字化之前，我们使用混频器将10 GHz至40 GHz范围内的振荡器信号转换为70 MHz附近的频带。我们使用零交叉时间戳和滑动傅立叶变换来分析波形，讨论这两种方法的不同局限性和优点，并将它们组合起来以获得跨越傅立叶频率f超过五十年的频率噪声频谱。对于具有由单个Ni_（80）Fe_（20）层或Co / Ni多层组成的自由层的器件，我们发现频率噪声频谱在大f时为白色，而在小f时变化为1 / f。交叉频率范围从≈10〜4 Hz到≈10〜6 Hz，并且在多层器件中1 / f分量更强。通过实际和模拟频谱分析仪的测量，我们发现1 / f频率噪声会随着测量时间的增加而引起振荡器频谱线的展宽和形状变化。我们的结果表明，无法从基于热（白）噪声源的模型中准确预测自旋扭矩振荡器的长期稳定性。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号