Ni-substituted sites and the effect on Cu electron spin dynamics of YBa2Cu3-xNixO7-delta

Article

关键词: IMPURITY-DOPED YBA2CU4O8;    NORMAL-STATE PROPERTIES;    MAGNETIC-IMPURITIES;    T-C;    LATTICE RELAXATION;    YBA2CU3O7-CU NQR;    SINGLE-CRYSTALS;    PAIR-BREAKING;    SUPERCONDUCTIVITY;    FLUCTUATION;   

DOI  :  10.1103/PhysRevB.66.134511

来源: SCIE

【 摘 要 】

We report a Cu nuclear quadrupole resonance experiment on magnetic impurity Ni-substituted YBa2Cu3-xNixO7-delta. The distribution of Ni-substituted sites and its effect on the Cu electron spin dynamics are investigated. Two samples with the same Ni concentration x=0.10 and nearly the same oxygen content but different T-c's were prepared: One is an as-synthesized sample (7-delta=6.93) in an oxygen gas (T(c)approximate to80 K), and the other is a quenched one (7-delta=6.92) in a reduced oxygen atmosphere (T(c)approximate to70 K). The plane-site Cu-63(2) nuclear spin-lattice relaxation for the quenched sample was faster than that for the as-synthesized sample, in contrast to the Cu-63(1) relaxation that was faster for the as-synthesized sample. This indicates that the density of plane-site Ni(2) is higher in the quenched sample, contrary to the chain-site Ni(1) density, which is lower in the quenched sample. From the analysis in terms of the Ni-induced nuclear spin-lattice relaxation, we suggest that the primary origin of suppression of T-c is associated with the nonmagnetic depairing effect of the plane-site Ni(2).

【 授权许可】

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