Production Procedure and Characterization of Zn-Doped Y-123 Superconducting Samples Prepared by Sol-Gel Method

Abstract

The superconducting YBa2Cu3−xZnxO7 (Y-123) bulk materials have been synthesized by using the sol-gel method. Samples are produced as undoped Y-123 and transition metal (Zn)-doped Y-123. Before the final heat treatment, the samples are calcined at 850 °C for 24 h. This process is repeated three times. Then, samples are sintered at 950 °C for 24 h in an air environment and at 500 °C for 5 h in an oxygen atmosphere. The synthesized products are characterized by XRD, R-T, and Vickers microhardness tester. The XRD investigation revealed that the prepared sample has an orthorhombic structure. According to XRD measurements, an orthorhombic structure has not changed with Zn doping. It was observed that undoped and Zn-doped samples have superconductivity properties by electrical measurements. $T_{\mathrm {c}}^{\text {onset}}$ is 89 K for undoped Y-123 sample, and the $T_{\mathrm {c}}^{\text {onset}}$ value decreases monotically with Zn addition. All samples show metallic behavior above $T_{\mathrm {c}}^{\text {onset}}$ temperature. As a result of Vickers microhardness measurements, it is observed that all samples have reverse indentation size effect (RISE) behavior.