La 139 NMR investigation of the charge and spin order in a La 1.885 Sr 0.115 CuO 4 single crystal
La 139 NMR investigation of the charge and spin order in a La 1.885 Sr 0.115 CuO 4 single crystal
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DOI：
10.1103/physrevb.97.064511
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发表时间：
2018-02
影响因子：
3.7
通讯作者：
A. Arsenault;S. Takahashi;T. Imai;Wei He;Yun-Shik Lee;M. Fujita
中科院分区：
文献类型：
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作者：
A. Arsenault;S. Takahashi;T. Imai;Wei He;Yun-Shik Lee;M. Fujita
由于核自旋和铜电子自旋之间存在适度的超精细相互作用，所以核磁共振适用于在磁性不稳定性附近研究铜酸盐的磁性。我们报道了高超导体单晶样品在宽温度范围内电荷和自旋序跃迁(K，K)的综合核磁共振测量结果。通过对核自旋到中心跃迁线宽的高精度测量，我们发现顺磁线展宽集精确地归因于平面内增强的自旋关联。在K以下还出现了额外的顺磁线展宽，这表明在平面的某些部分中的铜自旋处于三维磁序的边缘。然而，从沿平面有序的铜矩产生的静态超精细磁场只在K以下开始发展，在早期的Muon自旋旋转测量中发现了小体积分数的样品的Larmor进动。基于核-自旋-晶格弛豫速率的测量，我们还发现，电荷顺序不均匀地触发了铜自旋低频涨落的增强；越来越多的位受到朝着最终磁序的增强的低频自旋涨落的影响，而即使在更低的位置，越来越少的位继续表现出类似于最优超导相的行为。这些核磁共振结果证实了我们最近的核磁共振观察，即一个非常宽的、异常的翼状信号逐渐出现在下面，而正常行为的、较窄的主峰逐渐消失[T.Imai，Phys.B修订版96,224508(2017年)10.1103/PhysRevB.96.224508]。此外，我们还指出，在下面的低温区，低能自旋激发的增强强烈地依赖于外加磁场的大小和取向。
NMR is suited for investigations into magnetic properties of-based cuprates in the vicinity of their magnetic instabilities, owing to the modest hyperfine interactions betweennuclear spins and Cu electron spins. We report comprehensiveNMR measurements on a single-crystal sample of high-superconductorin a broad temperature range across the charge and spin order transitionsK,K). From the high-precision measurements of the linewidth for the nuclear spintocentral transition, we show that paramagnetic line broadening sets in precisely atdue to enhanced spin correlations within theplanes. Additional paramagnetic line broadening ensues belowK, signaling that Cu spins in some segments ofplanes are on the verge of three-dimensional magnetic order. A static hyperfine magnetic field arising from ordered Cu moments along theplane, however, begins to develop only belowK, where earlier muon spin rotation measurements detected Larmor precession for a small volume fractionof the sample. Based on the measurement ofnuclear-spin-lattice relaxation rate, we also show that charge order triggers enhancement of low-frequency Cu spin fluctuations inhomogeneously; a growing fraction ofsites is affected by enhanced low-frequency spin fluctuations toward the eventual magnetic order, whereas a diminishing fraction continues to exhibit a behavior analogous to the optimally superconducting phase even below. TheseNMR results corroborate our recentNMR observation that a very broad, anomalous winglike signal gradually emerges below, whereas the normally behaving, narrower main peak is gradually wiped out [T. Imai , Phys. Rev. B 96, 224508 (2017)10.1103/PhysRevB.96.224508]. Furthermore, we show that the enhancement of low-energy spin excitations in the low-temperature regime belowdepends strongly on the magnitude and orientation of the applied magnetic field.