Magnetic ordering in (Y1−xPrx)Ba2Cu3O7 as observed by muon-spin relaxation

Abstract

Zero-field positive muon-spin-relaxation (${\mathrm{\mu }}^{+}$SR) measurements on (${\mathrm{Y}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Pr}}_{\mathit{x}}$)${\mathrm{Ba}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ (x=1.0, 0.8, 0.6, 0.58, and 0.54) show clear evidence for antiferromagnetic ordering of the Cu moments within the Cu-O planes. Néel temperatures are approximately 285, 220, 35, 30, and 20 K for x=1.0, 0.8, 0.6, 0.58, and 0.54, respectively. For x=0.50 we observe a fast-relaxing component and a long-time tail of the muon polarization, reminiscent of spin-glass behavior. Superconductivity and spin-glass-like magnetism appear to coexist for x near 0.50. For x=1.0 the fully developed local magnetic field is ∼16 mT, but decreases to ∼12 mT at T=17 K, presumably due to the onset of additional ordering. The Néel temperature for oxygen-reduced ${\mathrm{PRBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_6$ is approximately 325 K.