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We report NMR lineshape, spin-lattice relaxation time T[sub 1], and spin-spin relaxation time T[sub 2] data at 17 MHz (8.07 T) for [sup 89]Y in the copper-oxide spin-chain compound Ca[sub 2+x]Y[sub 2-x]Cu[sub 5]O[sub 10]. For x = 0, a broad, asymmetric line with width Δν ≈ 90 kHz is observed for T = 250-300 K. The spectra exhibit an appreciable average shift (ΔH/H ≈ +0.7%) and sharpen at lower temperature, possibly due to increasing intrachain ferromagnetic correlations. T[sub 1] and T[sub 2] decrease with decreasing temperature. The T[sub 1] data imply a short correlation-time limit, with τ[sub e] = 3-5 × 10[sup -11] s. The T[sub 2] data apparently include a contribution from dipolar interactions with copper nuclei. Relaxation time data for a doped (x=0.5) compound surprisingly show more rapid relaxation. [ABSTRACT FROM AUTHOR]

We report measurements of NMR spin-lattice (T1 ) and spin-spin (T2 ) relaxation times for89 Y in the parent structure of the electron–doped copper–oxide superconductors. T1 data exhibit non–exponential recovery with T1 ≍ 20 s. T2 decreases rapidly with temperature above the Néel temperature, but remains constant above 425 K. We discuss these behaviors by considering fluctuating antiferromagnetic spin clusters associated with oxygen defects. [ABSTRACT FROM AUTHOR]