Intrinsic electron doping in nominal “nondoped” superconducting (La,Y)2CuO4 thin films grown by magnetron sputtering
The superconducting nominal “nondoped” La1.85Y0.15CuO4 (LYCO) thin films are prepared by magnetron sputtering. The best TC0 of more than 13K is achieved in the optimal films with highly pure c-axis oriented T′-type structure. The quasiquadratic temperature dependence of resistivity and the negative Hall coefficient in the normal state, effect of oxygen content are all quite similar to the known Ce-doped n-type cuprate superconductors, suggesting the electron-doping nature in T′-LYCO. The charge carriers are considered to arise from oxygen deficiency.