Controlled microwave irradiation for the synthesis of YBa2Cu3O7-x superconductors

For synthesizing a high-quality YBa2Cu3O7-x superconductor using a domestic microwave oven without any post-heat treatment, the power;and time of micr owave irradiation are controlled by monitoring continuously the temperature of the microwave-heated sample. The temperature is measured by means of a metal-sheathed chromel-alumel thermocouple which is installed in the oven i n the proper way. The conditions of the sample inside the oven are almost t he same as the sample environment proposed by Rare et at [Jpn. J. Appl. Phy s. 36 (1997) L1291]. The maximum monitoring temperature where crystal growt h occurs rapidly for a high-quality YBa2Cu3O7-x superconductor is shown to be about 500 degrees C which is much lower than the maximum heating tempera ture. in the conventional method.