Magnetic Study of the Low-Temperature Anomalies in the Optimally Doped PrBCO Compound

The anomalous magnetic properties of a non-superconducting PrBa2Cu3O6+x (or PrBCO) compound in an optimally doped oxygen state of concentration (x = 0.95) are investigated at low temperatures using magnetic measurements such paraprocess magnetic susceptibility chi(H)(T) under different values of a DC magnetic field H up to 8 T and isothermal magnetizations M-T(H) with H up to 2.1 T. The temperature dependences of the derivatives of chi(H)(T) indicate a significant decrease with increasing H of the Neel temperature T-N = 14K associated with antiferromagnetic (AFM) Pr ordering. The AFM-paramagnetic phase transition remains well defined even at 8 T, whereas the small anomaly at T-2 = 10.5 K, which is due to the spin reorientation phase transition already reported before, seems clearly highlighted at 2 T but entirely suppressed above 6 T. A weak ferromagnetic (WFM) contribution is revealed below T-N with more evidence particularly below the low critical point T-cr = 4-5K whose anomaly is still visible with increasing H up to 8 T. Weak field-induced transitions between AFM and WFM phases are observed in the derivatives of M-T(H) at a low transition field (H-t < 1 T). All results are discussed and compared with those found in previous works.