Phys. Rev. B 63, 144508 (2001) [11 pages]Glassy spin freezing and NMR wipeout effect in the high-Tc superconductor La1.90Sr0.10CuO4: Critical discussion of the role of stripesReceived 11 October 2000; revised 5 December 2000; published 19 March 2001 We report on 139La and 63Cu NMR/NQR measurements in the high-Tc superconductor La1.90Sr0.10CuO4, with Tc=26.5 K. Spin fluctuations probed by 139La spin-lattice relaxation (T1) continuously slow down on cooling through Tc. We argue that spin freezing and superconductivity are bulk effects in this sample. Thus both phenomena have to coexist microscopically. The distribution of 139La T1 values at low temperature reveals a wide spread of spin fluctuation frequencies in CuO2 planes. A simple estimate shows that 63Cu nuclei at sites where electronic fluctuations are the slowest are not observable (wipeout effect) because relaxation times are too short. This means that the 63Cu NQR wipeout, observed in this sample, can be explained primarily by slow magnetic, rather than charge, fluctuations. The magnetic origin of the wipeout is still compatible with a connection between wipeout and charge order [as proposed by Hunt et al., Phys. Rev. Lett. 82, 4300 (1999)], but this connection is indirect. On the other hand, since the wipeout fraction is not an intensive quantity it cannot define a proper order parameter and cannot be used by itself as a criterion for the existence of a stripe phase. © 2001 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.63.144508
DOI:
10.1103/PhysRevB.63.144508
PACS:
74.72.Dn, 76.60.-k, 74.25.Ha
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