Tunable superconductivity in parent cuprate Pr₂CuO_4±δ thin films

We studied the role of oxygen in Pr₂CuO_4±δ thin films fabricated by the polymer assisted deposition method. The magnetoresistance and Hall resistivity of Pr₂CuO_4±δ samples were systematically investigated. It was found that with decreasing oxygen content, the low-temperature Hall coefficient (R_H) and magnetoresistance changed from negative to positive, similar to those with the increase of Ce-doped concentration in R_2-xCe_xCuO₄ (R=La, Nd, Pr, Sm, Eu). In addition, we observed that the dependence of the superconducting critical temperature T_c with R_H for the Pr_2-xCe_xCuO₄ perfectly overlapped with that of Pr₂CuO_4±δ. These findings point to the fact that the doped electrons induced by the oxygen removal are responsible for the superconductivity of the T'-phase parent compounds.