Y $_{0.98}$ Yb $_{0.02}$ Ba $_{2}$ Cu $_{3}$ O $_{x}$中Yb $^{3+}$自旋弛豫的电子顺磁共振研究
Probing the Yb$^{3+}$ spin relaxation in Y$_{0.98}$Yb$_{0.02}$Ba$_{2}$Cu$_{3}$O$_{x}$ by Electron Paramagnetic Resonance
摘要：
本文用电子顺磁共振（EPR）研究了YBaPDMATHABMN Cu $_{3}$ O $_{x}$（$6<x<7$）中Yb $^{3+}$的弛豫。结果发现，电子和声子过程有助于Yb $^{3+}$弛豫。的声子部分的松弛具有指数的温度依赖性，这可以解释通过拉曼过程通过耦合到高能量（$\sim$ 500 K）的光学声子或Orbach样的过程通过激发的振动水平的Cu $^{2+}$离子（本地化Slonczewski模式）。在具有最大氧掺杂$x$ =6.98的样品中，弛豫的电子部分在正常状态下遵循柯林加定律，并且在$T_{c}$以下强烈降低。通过比较掺Zn和不掺Zn的样品，证明了超导带隙的打开是导致YBaPDMATHABMN CuPDMATHABMO O $_{6.98}$中Yb $^{3+}$弛豫急剧减小的原因。结果表明，尽管Yb $^{3+}$的电子弛豫速率与原子核弛豫速率有很大的差异，但其电子弛豫的温度依赖性与$^{63}$ Cu和$^{17}$ O的温度依赖性相同.
英文摘要：
The relaxation of Yb$^{3+}$ in YBa$_{2}$Cu$_{3}$O$_{x}$ ($6<x<7$) was studied using Electron Paramagnetic Resonance (EPR). It was found that both electronic and phononic processes contribute to the Yb$^{3+}$ relaxation. The phononic part of the relaxation has an exponential temperature dependence, which can be explained by a Raman process via the coupling to high-energy ($\sim$500 K) optical phonons or an Orbach-like process via the excited vibronic levels of the Cu$^{2+}$ ions (localized Slonczewski-modes). In a sample with a maximum oxygen doping $x$=6.98, the electronic part of the relaxation follows a Korringa law in the normal state and strongly decreases below $T_{c}$. Comparison of the samples with and without Zn doping proved that the superconducting gap opening is responsible for the sharp decrease of Yb$^{3+}$ relaxation in YBa$_{2}$Cu$_{3}$O$_{6.98}$. It was shown that the electronic part of the Yb$^{3+}$ relaxation in the superconducting state follows the same temperature dependence as $^{63}$Cu and $^{17}$O nuclear relaxations despite the huge difference between the corresponding electronic and nuclear relaxation rates.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
