Rapid Preparation of YBa₂Cu₃O_y by Using a Domestic Microwave Oven with a SiC Susceptor

Abstract

Nearly single-phase samples of high-Tc superconductors of the Y-123(YBa₂Cu₃O_y) phase have been prepared using a domestic microwave oven. Since it is significantly important to control temperature of the sample for microwave heating, the samples were placed into thermally insulated box coated with SiC (susceptor). Weighting of Y₂O₃, BaO, and CuO with a molar ratio were carried out and mixied with agate mortar for 1 hour. Samples (12 mm in diameter) were pressed with mold at 30 MPa and heated by microwave (2.45 GHz, and 700 W) with the susceptor. The temperature in the susceptor was kept at 850 °C for 10 minutes, and the samples of Y-123 were prepared. The produced sample showed superconductive transition temperature (Tc) by 92 K, and had zero resistance by 85 K. These properties for samples prepared by microwave heating were almost consistent with the samples produced by the conventional solid phase process. Properties of Y-123 sintered by various susceptors were mainly investigated. These results showed that microwave sintering was suitable for rapid heat-treatments of a copper oxide superconductor.