Magnetic Ground State of Pr$_{0.89}$LaCe$_{0.11}$CuO$_{4+\alpha-\delta}$ with Varied Oxygen Depletion Probed by Muon Spin Relaxation

TL;DR

This study investigates the magnetic ground state of an electron-doped cuprate superconductor with varied oxygen depletion using muon spin relaxation, revealing weak random magnetism linked to excited Pr$^{3+}$ ions and unaffected by oxygen depletion levels.

Contribution

It provides new insights into the magnetic behavior of Pr$_{1-x}$LaCe$_x$CuO$_{4+eta-eta}$ across different oxygen depletion levels using muon spin relaxation.

Findings

Weak random magnetism observed throughout the crystal.

Random moments are associated with excited Pr$^{3+}$ ions.

Magnetism is independent of oxygen depletion level.

Abstract

The magnetic ground state of an electron-doped cuprate superconductor Pr$_{1-x}$LaCe$_x$CuO$_{4+\alpha-\delta}$ ($x=0.11, \alpha\simeq0.04$) has been studied by means of muon spin rotation/relaxation (\msr) over a wide variety of oxygen depletion, $0.03\le\delta\le0.12$. Appearance of weak random magnetism over entire crystal volume has been revealed by a slow exponential relaxation. The absence of $\delta$-dependence for the random magnetism and the multiplet pattern of muon Knight shift at higher fields strongly suggest that the random moments are associated with excited Pr$^{3+}$ ions under crystal electric field.