Muon spin relaxation study of the Cu spin dynamics in electron-doped high-TcsuperconductorPr0.86LaCe

Abstract

Muon-spin-relaxation ͑SR͒ measurements have been performed for the partially Zn-substituted electrondoped high-T c superconductor Pr 0.86 LaCe 0.14 Cu 1−y Zn y O 4+␣−␦ with y = 0 -0.05 and the reduced oxygen content ␦ = 0 -0.09, in order to investigate nonmagnetic Zn-impurity effects on the Cu-spin dynamics. For all the measured samples with 0.01Յ ␦ Յ 0.09, it has been found that a fast depolarization of muon spins is observed below 100 K due to the effect of Pr 3+ moments and that the SR time spectrum in the long-time region above 5 sec increases with decreasing temperature at low temperatures below 30 K possibly due to slowing down of the Cu-spin fluctuations assisted by Pr 3+ moments. No Zn-induced slowing down of the Cu-spin fluctuations has been observed for moderately oxygen-reduced samples with 0.04Յ ␦ Յ 0.09, which is very different from the SR results of La 2−x Sr x Cu 1−y Zn y O 4 . The possible reason may be that there are no dynamical stripe correlations of spins and electrons in the electron-doped high-T c cuprates or that the effect of Pr 3+ moments on the SR spectra is stronger than that of a small amount of Zn impurities.

Evolution of the Electronic State through the Reduction Annealing in Electron-Doped Pr1.3-xLa0.7CexCuO4+δ(x=0.10) Single Crystals: Antiferromagnetism, Kondo Effect, and Superconductivity

“…[11][12][13] The quality of the crystals was checked by x-ray back-Laue photography and x-ray diffraction to be good. The composition of as-grown crystals was analyzed by the inductively coupled plasma (ICP) analysis to be Pr 1.17 La 0.73 Ce 0.10 Cu 1.00 O 4+δ which is close to the nominal composition.…”

Muon-spin relaxation study of the spin correlations in the overdoped regime of electron-doped high- Tc cuprate superconductors

“…RESULTS AND DISCUSSION Figure 2 shows the ZF-µSR time spectra of the reduced crystals of PLCCO with x = 0.17 and 0.20 together with x = 0.14. [20] In both x = 0.17 and 0.20, the depolarization of muon spins is slow at a high temperature of 200 K owing to the very small nuclear dipole field randomly oriented at the muon site, indicating an almost paramagnetic state of Cu spins. With decreasing temperature, the depolarization of muon spins becomes fast as seen in x = 0.14 due to static random magnetism of small magnetic moments of Pr 3+ ions induced by the mixing of the excited state in the crystal electric field.…”

“…With decreasing temperature, the depolarization of muon spins becomes fast as seen in x = 0.14 due to static random magnetism of small magnetic moments of Pr 3+ ions induced by the mixing of the excited state in the crystal electric field. [20,25] For x = 0.14, the development of the Cu-spin correlation is characterized by the increase in the asymmetry in the long-time region above ∼ 4 µsec with decreasing temperature shown in Fig. 2(a), [20] which is due to the recovery of the asymmetry toward 1/3 in a magnetically ordered state.…”

Cu-spin fluctuations in hole- and electron-doped high-Tc superconducting cuprates relating to stripe pinning

“…The second aim is to investigate impurity effects on the Cu-spin dynamics in electrondoped Pr 1-x LaCe x Cu 1-y Zn y O 4+α-δ focusing on the validity of the stripe-pinning model also in the electron-doped cuprate [8].…”

“…ZF-μSR time spectra of electron-doped Pr 0.86 LaCe 0.4 Cu 1-y Zn y O 4+α-δ with y = 0, 0.01, 0.02, 0.05 and large δ values (0.04 < δ ≤ 0.09)[8].…”