The magnetization properties of a flux-grown NdBa2Cu3O7-δ (Nd123) single crystal were investigated by measuring DC magnetization hysteresis (M-H) loops in a wide temperature range (10-92 K) and for applied fields parallel (H ∥ c) and perpendicular (H ∥ a-b) to the c-axis of the sample. For both field directions, temperature-dependent fishtail peaks in the M-H loops are clearly observed at high temperatures above 70 K, and all the data could be scaled to a single master curve with the hysteresis loop width ΔM versus H plot when they are normalized with the peak field Hpk and its magnetization value ΔMpk, respectively. This indicates that the origins of the peak effect and the pinning are identical for this temperature range. We have also found that Hpk and the irreversibility field Hirr scale with the reduced temperature, t = T/Tc (Tc: critical temperature), and follow the relationship Hirr ∝ (1 - t)n with a power n of 1.1-1.3. The anisotropy parameters γpk of Hpk (≅ 6.8) and γirr of Hirr (≅ 4.7) were deduced from the angular dependence of Hpk and Hirr at 88 K. We emphasize that all the present results support our proposal that the peak effect in the Nd123 originates from the localized Nd-Ba substituted regions with depressed Tc.
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