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

Abstract

The magnetic ground state of an electron-doped cuprate superconductor Pr$_{1-x}$LaCe$_x$CuO$_{4+α-δ}$ ($x=0.11, α\simeq0.04$) has been studied by means of muon spin rotation/relaxation (\msr) over a wide variety of oxygen depletion, $0.03\leδ\le0.12$. Appearance of weak random magnetism over entire crystal volume has been revealed by a slow exponential relaxation. The absence of $δ$-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.