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

M. -H. Julien·P. Carretta·F. Borsa
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Abstract

NQR 139La and 63Cu spin-lattice relaxation rate (1/T_1) 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/T_1 on cooling. While the onset of diamagnetism occurs at Tc=8 K, 1/^{139}T_1 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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M. -H. Julien, P. Carretta, F. Borsa. 1999-09-23. NQR Study of Spin-Freezing in Superconducting La2-xSrxCuO4: The Example of x=0.06. https://arxiv.org/abs/cond-mat/9909351

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