Growth of PrFeAsO1-y single crystals and its characterization

Single crystals of oxygen deficient oxypnictide superconductor PrFeAsO1-y have been grown by using belt-type anvil high-pressure synthesis apparatus. Superconducting transition temperature (Tc) of the obtained single crystal is 45 K, and typical size is about 800 x 1000 x 30 μm3. In-plane electrical resistivity shows s-shaped behavior, and can well be fitted by T1.2 temperature dependence near 150 K. In addition, we obtained non-superconducting parent single crystal by annealing the as-grown single crystal under ambient pressure. Resistivity of parent single crystal is characterized by the kink near 150 K corresponding to the structural transition, and the structure near 12 K, which is thought to be originating from the magnetic order of Pr ion.