NQR Study of Spin-Freezing in Superconducting La2-xSrxCuO4: The Example of x=0.06

1999/09/23 by M. -H. Julien, P. Carretta, F. Borsa
Physics and Astronomy · #cond-mat.supr-con #cond-mat.str-el

paper · pdf

published as Appl. Magn. Res. 19, 287-296 (2000) · Submitted to Applied Magnetic Resonance (Proceedings of the specialized colloque Ampere "EPR, NMR, NQR in Solid State Physics: Recent Trends") 6 pages incl. 1 figure

arxiv created 1999/09/23 · arxiv updated 2009/11/30

Abstract

NQR 139La and 63Cu spin-lattice relaxation rate (1/T₁) measurements in a La1.94Sr0.06CuO4 single crystal are described. Slowing-down of Cu2+ spin fluctuations is evidenced through a dramatic increase of 139La 1/T₁ on cooling. While the onset of diamagnetism occurs at Tc=8 K, 1/¹³⁹T₁ has a peak at Tg~5 K, when the characteristic frequency of magnetic fluctuations reaches the NQR frequency nu_Q~19 MHz. In agreement with a number of previous studies, these results show that the so-called "cluster spin-glass" phase persists in the superconducting regime. Issues concerning the coexistence of the two phases are discussed.

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