Y-Ba-Cu-O系セラミックス超伝導体の作製

Abstract

The zero resistance and the complete Meissner effect of the Y-Ba-Cu-O ceramics superconductor have been observed. The zero resistance critical temperature about 90 K has been measured by the conventional four-probe technique. The specimen of the superconductor has been fabricated as follows. Powder materials of Y_2O_3,BaCO_3 and CuO are mixed and calcined at 950℃ for 5 hours in air. The powder is grinded and pressed into a pellet by 1.5t/cm^2. The pellet is sintered at 950℃ for 5 hours in air and after that it is furnace-cooled to room temperature or annealed in oxygen atmosphere. The sample size is 10 mm diameter and 1mm thickness after the sintering. The structure has been analysed with thermogravimetric analyser, X-ray diffraction and scanning electron microscope. The crystal structure has been confirmed to be essentially of a layered orthorhombic perovskite type.