Magnetic ordering in (Y sub 1 minus x Pr sub x )Ba sub 2 Cu sub 3 O sub 7 as observed by muon-spin relaxation

Zero-field positive muon-spin-relaxation ({mu}{sup +}SR) measurements on (Y{sub 1{minus}{ital x}}Pr{sub {ital x}})Ba{sub 2}Cu{sub 3}O{sub 7} ({ital 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. Neel temperatures are approximately 285, 220, 35, 30, and 20 K for {ital x}=1.0, 0.8, 0.6, 0.58, and 0.54, respectively. For {ital 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 {ital x} near 0.50. For {ital x}=1.0 the fully developed local magnetic field is {similar to}16 mT, but decreases to {similar to}12 mT at {ital T}=17 K, presumably due to the onset of additional ordering. The Neel temperature for oxygen-reduced PRBa{sub 2}Cu{sub 3}O{sub 6} is approximately 325 K.