Absence of the impurity-induced magnetic order in the electron-doped high-T_c_ cuprates Pr_0.86_LaCe_0.14_Cu_1-y_(Zn, Ni)_y_O_4_

TL;DR

This study investigates the effects of Zn and Ni impurities on Cu-spin dynamics in electron-doped cuprates, finding no impurity-induced magnetic order, contrasting with hole-doped counterparts, and discussing possible reasons.

Contribution

It provides experimental evidence that impurity substitution does not induce magnetic order in electron-doped cuprates, unlike in hole-doped systems, challenging existing understanding.

Findings

No impurity-induced slowing down of Cu-spin fluctuations in electron-doped cuprates.

Long-range antiferromagnetic order observed only in pristine, minimally oxygen-reduced samples.

Impurity effects differ significantly between electron- and hole-doped high-T_c cuprates.

Abstract

Zero-field muon-spin-relaxation measurements have been carried out in order to investigate the Zn- and Ni-substitution effects on the Cu-spin dynamics in the electron-doped Pr_0.86_LaCe_0.14_Cu_1-y_(Zn, Ni)_y_O_4+\alpa-\delta_ with y = 0, 0.01, 0.02, 0.05 and different values of the reduced oxygen content \delta(\delta \le 0.09). For the samples with y = 0 and very small \delta values of \delta < 0.01, a muon-spin precession due to the formation of a long-range antiferromagnetic order has been observed at low temperatures below \~ 5 K. For the moderately oxygen-reduced samples of 0.01 \le \delta \le 0.09, on the contrary, no muon-spin precession has been observed and the temperature dependence of the spectra is similar to one another regardless of the y value. That is, no impurity-induced slowing down of the Cu-spin fluctuations has been detected, which is very different from the results of the hole-doped high-T_c_ cuprates. The reason is discussed.