Abstract
We have investigated slightly underdoped NdBa 2(Cu,Zn,Ni) 3O 7− δ with magnetic Ni and non-magnetic Zn impurities by 63Cu nuclear quadrupole resonance (NQR). The larger ionic radius of the Nd compared to Y made it possible to incorporate higher amounts of Zn and Ni impurities (up to 12% in our samples), and thereby superconductivity is completely suppressed. The 63Cu NQR spectra are comparable to similar doped YBCO samples, but are shifted about ≈1.5 MHz to higher frequencies. By doping the samples with Ni the spectra are moderately broadened, whereas the broadening is stronger for Zn doping. The spin lattice relaxation rate, T 1 - 1 , is drastically enhanced by the large Nd moment, and thereby the pseudo gap is not visible in all of these samples.
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