MAGNETIC-ORDERING IN (Y1-XPRX)BA2CU3O7 AS OBSERVED BY MUON-SPIN RELAXATION

Zero-field positive muon-spin-relaxation (+SR) measurements on (Y1-xPrx)Ba2Cu3O7 (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 PRBa2Cu3O6 is approximately 325 K. © 1990 The American Physical Society.