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首页> 外文会议>Conference on Noise as a Tool for Studying Materials Jun 2-4, 2003 Santa Fe, New Mexico, USA >Low frequency noise in charge ordered system near the charge-ordering transition and in the current induced destabilized state
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Low frequency noise in charge ordered system near the charge-ordering transition and in the current induced destabilized state

机译：电荷排序系统中靠近电荷排序过渡且处于电流感应不稳定状态的低频噪声

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摘要

We have investigated the dynamics of coexisting phases in the Charge Ordered (CO) manganite Pr_(0.63)Ca_(0.37)MnO_3 using the technique" of conductance noise spectroscopy. We note that close to the CO transition temperature T_(CO) the spectral power Sv(f)/V~2 deviates significantly from the 1/f frequency dependence for f ≤0.125Hz. Our analysis shows that this deviation can be described by a single frequency Lorentzian with corner frequency f_C in addition to the usual broadband 1/f noise. Such a Lorentzian contribution to S_v(f)/V~2 can come from a two level system (TLS). In the time series this shows up as RTN. For T ≤ T_(CO) the system shows the onset of non-linear conduction close to a threshold value J_(dc) =J_(th). For J_(dc) < J_(th) the noise spectra is mainly 1/f in nature. For J_(dc) > J_(th) a large low frequency component of noise (characterized again by a frequency f_C) appears. We associate fc with the relaxation time τ_C of the TLS fluctuator so that τ_C = 1/f_C. For thermal activation of the TLS the temperature dependence of f_C will follow f_C=f_0exp(-E_a/κBT) where E_a is an energy barrier. The value of f_C shows an increase with J_(dc) showing that the value of the activation energy E_a is being lowered by the applied bias.
机译：我们使用电导噪声光谱技术研究了带电荷有序（CO）锰矿Pr_（0.63）Ca_（0.37）MnO_3中共存相的动力学。我们注意到，接近CO转变温度T_（CO）的光谱功率当f≤0.125Hz时，Sv（f）/ V〜2明显偏离1 / f频率依赖性，我们的分析表明，除了通常的宽带1 / f外，该偏差还可以用拐角频率为f_C的单频洛伦兹定律来描述。噪声对S_v（f）/ V〜2的洛伦兹贡献可能来自两级系统（TLS），在时间序列中显示为RTN，对于T≤T_（CO），系统显示出线性传导接近阈值J_（dc）= J_（th）。对于J_（dc） J_（th）a出现较大的噪声低频分量（再次由频率f_C表征），将fc与TLS波动器的弛豫时间τ_C关联，使得τ_C= 1 / f_C。 TLS的正常激活后，f_C的温度依赖性将遵循f_C = f_0exp（-E_a /κBT），其中E_a是能量屏障。 f_C的值随J_（dc）的增加而增加，表明激活能量E_a的值因施加的偏压而降低。

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