Very recently, by inspecting large sets of data across all families of superconducting cuprates, it became obvious that the prevailing nuclear magnetic resonance (NMR) interpretation of cuprate properties is not adequate, as it does not account for the differences between the families, as well as common characteristics beyond simple temperature dependence. From the most abundant planar Cu shift data, one concludes readily on two electronic spin components with different doping and temperature dependencies. Their uniform response that causes NMR spin shifts consists of a doping-dependent component due to planar O, and another due to spin in the planar copper 3d(x² − y²) orbital, where the latter points opposite the field direction. Planar Cu relaxation was found to be rather ubiquitous (except for La_2−xSr_xCuO₄), and Fermi liquid-like, i.e., independent of doping and material, apart from the sudden drop at the superconducting transition temperature, T_c. Only the relaxation anisotropy is doping and material dependent. We showed previously that one can understand the shifts within a two-component scenario, but we failed with a model to account for the relaxation. Here, we suggest a slightly different shift scenario, still based on the two components, by introducing different hyperfine couplings, and, importantly, we are able to account for the Cu nuclear relaxation and its anisotropy for all materials, including also La_2−xSr_xCuO₄. The results represent a solid framework for theory.

中文翻译：

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核磁共振位移和弛豫与超导铜酸盐的电子自旋

最近，通过检查所有超导铜酸盐家族的大量数据，很明显，主要的核磁共振（NMR）对铜酸盐性质的解释是不充分的，因为它也没有考虑到家族之间的差异。作为简单的温度依赖性以外的共同特征。从最丰富的平面Cu位移数据中，很容易得出结论，得出了两种电子自旋成分，它们具有不同的掺杂和温度依赖性。它们引起NMR自旋位移的均匀响应由平面O引起的掺杂相关成分和平面3d（x ² - y ²）轨道，后者指向相反的磁场方向。发现平面Cu弛豫非常普遍（除了La _{2− x} Sr _x CuO ₄），并且费米呈液态，即与掺杂和材料无关，除了在超导转变温度T _c突然下降之外。。仅弛豫各向异性是掺杂和材料依赖性的。先前我们证明了一个人可以理解两部分情况下的变化，但是我们未能使用一种模型来解释这种松弛。在这里，我们通过引入不同的超精细偶合，基于两个成分，提出了一个略有不同的位移方案，并且重要的是，我们能够解释所有材料（包括La _{2- x）}的Cu核弛豫及其各向异性Sr _x CuO ₄。结果代表了坚实的理论框架。