Single-spin fluid, spin gap, and d-wave pairing in YBa2Cu4O8: A NMR and NQR study.
Single-spin fluid, spin gap, and d-wave pairing in YBa2Cu4O8: A NMR and NQR study.
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DOI：
10.1103/physrevb.50.6416
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发表时间：
1994-09
期刊：
影响因子：
--
通讯作者：
Bankay;Mali;Roos;Brinkmann
中科院分区：
文献类型：
--
作者：
Bankay;Mali;Roos;Brinkmann
本文给出了82-K超导体${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{4}$${\mathrm{O}}_{8}$.的正常态和超导态的核磁共振和核四极共振研究结果在8.5K到300K的温度范围内，铜和O骑士位移张量的各个分量都表现出强烈但相似的温度依赖关系，这支持了平面和链中只有一个自旋分量的图景，尽管其磁化率不同。氧数据服从Korringa关系。这可以解释为电子系统远离反铁磁波矢的费米-液体行为。平面铜位移张量和O位移张量与温度的关系以及平面铜自旋晶格弛豫速率表明，在{\mathit{T}}_{\mathit{c}}$以上有一个伪自旋隙打开。平面O位和铜位的1/${\mathit{T}}_{1}与温度的关系非常不同，表明O位的反铁磁关联自旋涨落的作用减弱。这些数据支持了${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{4}$${\mathrm{O}}_{8}$是d波超导体的结论。三个数据集提供了证据：链Knight位移，平面铜和氧弛豫速率的比率，以及这些速率的单独低温行为。
We present results of $^{17}\mathrm{O}$ and $^{63,65}\mathrm{Cu}$ nuclear magnetic resonance (NMR) and nuclear quadrupolar resonance (NQR) studies in the normal and superconducting state of the 82-K superconductor ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{4}$${\mathrm{O}}_{8}$. The various components of the Cu and O Knight-shift tensors show strong but similar temperature dependences over the temperature range from 8.5 to 300 K in both the ${\mathrm{CuO}}_{2}$ planes and the chains, supporting the picture that there is only one spin component in the planes and the chains, although with different susceptibilities. The oxygen data obey the Korringa relation. This may be interpreted as Fermi-liquid behavior of the electronic system far away from the antiferromagnetic wave vector. The temperature dependence of both the planar Cu and O shift tensors and the planar Cu spin-lattice relaxation rate suggest the opening of a pseudo-spin-gap well above ${\mathit{T}}_{\mathit{c}}$. The very different temperature dependence of 1/${\mathit{T}}_{1}$ at the planar O and Cu sites points to the reduced role of the antiferromagnetic correlated spin fluctuations at the O site. The data favor the conclusion that ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{4}$${\mathrm{O}}_{8}$ is a d-wave superconductor. Evidence is provided by three data sets: the chain Knight shifts, the ratio of the planar copper and oxygen relaxation rates, and the individual low-temperature behavior of these rates.