The Suppression of Superconductivity in Heavily Overdoped Regime of Eu<sub>1.81</sub>Ce<sub>0.19</sub>CuO<sub>4+</sub><i><sub>α</sub></i><i><sub>-</sub></i><i>&

The suppression of superconductivity ( T c ) in electron-doped superconducting materials Eu 1.81 Ce 0.19 Cu 1- y Zn y O 4+ α - δ (ECCZO) heavily overdoped regimes by nonmagnetic impurity Zn with concentration of y = 0, 0.01, 0.02, and 0.03 has been successfully investigated by using XRD and SQUID measurements. All samples were synthesized using the solid-state reaction method. The crystal structure obtained from XRD measurements has a tetragonal T° structure, which matches the crystal structure of electron-doped superconductors in general. The addition of Zn impurity shows no change in the crystal structure, but there is a decrease in the α -lattice and an increase in the c -lattice, unit cell volume, and Cu-O bond length. This causes the distance between the charge reservoir and the conduction layer to increase and affects the disappearance of T c . Magnetic susceptibility measurements using SQUID were carried out under FC (Field Cooling) conditions with temperatures between 2 - 30 K with a field of 5 Oe. The sample with y = 0 has diamagnetic properties with a superconductivity value ( T c ) of about 11 K. The addition of Zn impurities succeeded in suppressing superconductivity as indicated by the disappearance of T c , so that the sample is in the ground state. The Curie constant and the effective magnetic moment decrease with increasing Zn concentration. This is probably due to the decrease in Cu 2+ when the non-magnetic Zn 2+ atoms were added, therefore the overall value of the µ eff decreases when Zn 2+ substitutes some Cu 2+ . This result is different from that described by Abrikosov-Gor’kov theory in the hole-doped high- T c cuprates.