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

Using the zero-field-muon-spin-relaxation ({mu}SR) technique we have found clear evidence for antiferromagnetic ordering of Cu moments within the CuO planes of (Y{sub 1-x}Pr{sub x})Ba{sub 2}Cu{sub 3}O{sub 7}. The Neel temperatures are approximately 285 K, 220 K, 35 K, 30 K, and 20 K for x = 1, 0.8, 0.6, 0.58, and 0.54, respectively. For x = 0.50 we observe a fast-relaxing component of the muon polarization in addition to a long-time tail, reminiscent of spin-glass behavior. This region of the phase diagram (0.5{le}x{le}0.54) corresponds to the existence of both superconductivity and magnetism. The fully developed local magnetic field for x>0.54 is found to be {approximately}16 mT, but decreased to {approximately}12 mT at T = 17 K for the x = 1 sample, presumably due to the onset of Pr-ion ordering. Magnetic ordering also occurs in PrBa{sub 2}Cu{sub 3}O{sub 6}; the Neel temperature is {approximately}325 K. 7 refs., 4 figs