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Cu NQR study of host and guest spin dynamics in impurity-doped YBa2Cu4O8

Y. Itoh·T. Machi·N. Watanabe·N. Koshizuka
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Abstract

We present the planar 63Cu nuclear spin-lattice relaxation study of impurity-doped YBa2(Cu1-xMx)4O8 (M=Ni, Zn) at T=4.2-300 K with Cu nuclear quadrupole resonance (NQR) spin-echo technique. In the light of an impurity-induced NQR relaxation theory, we estimated the host Cu nuclear spin-lattice relaxation time (T1)HOST, the impurity-induced Cu nuclear spin-lattice relaxation time (t1), and the wipeout region around the impurity in the superconducting state. The pseudo spin-gap behavior of the host Cu antiferromagnetic spin fluctuation above Tc is not readily removed by a small amount of the impurity. The Zn-induced non-Korringa behavior of (T1)HOST below Tc is in sharp contrast to the doping effect of the magnetic impurity Ni.

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Y. Itoh, T. Machi, N. Watanabe, N. Koshizuka. 2001-07-10. Cu NQR study of host and guest spin dynamics in impurity-doped YBa2Cu4O8. https://doi.org/10.1016/s0921-4534(01)00196-4

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