Probing spatial correlations in the inhomogeneous glassy stae of the cuprates by cu nmr.

[摘要] We discuss the crossover of the form of the Cu NMR spin echo decay at the onset of Cu wipeout in lanthanum cuprates. Experimentally, the echo decay undergoes a crossover from Gaussian to exponential form below the temperature where the Cu NMR intensity drops. The wipeout and the change in behavior both arise because the nuclei experience spatially inhomogeneous spin fluctuations at low temperatures. We argue that regions where the spin fluctuations remain fast are localized on length scales of order 1-2 lattice spacings. The inhomogeneity is characterized by the local activation energy E(alpha)(r) ate the functional form E(alpha)(r) for points where E(alpha)(r) is approximately 0.

[发布机构] Technical Information Center Oak Ridge Tennessee

[学科分类] 工程和技术（综合）

[关键词] Spatial distribution;Cuprates;Copper;Nuclear magnetic resonance;Lanl