ELECTRICAL AND MAGNETIC-PROPERTIES OF THE HIGH-TC SUPERCONDUCTORS (Y1-XMX)BA2CU3OY AND Y(BA1-XMX)2CU3OY (M=MG, CA, SR, BA)

The superconducting state of YBa2Cu3Oy substituted at the II a group was investigated by X-ray powder diffraction, iodometric titration, electrical resistivity and magnetization measurements. The T(c) is shifted to low temperature by the substitution of Y or Ba from a heavy atom to light atom at x = 0.1, and depends on the ionic radius. In the results obtained from the magnetic hysteresis loop, it is interesting that in the case of the substitution of Ca for x = 0.1, the magnetization for Y is larger than that for Ba with decreasing temperature, and the magnetization in the case of Ba for Y is rapidly lowered at x = 0.1.