To provide a high temperature superconductor of ceramics to be use as a current limiter of an AC line.
A high temperature superconductor 1 of ceramics includes a bypass layer 2 whose electric resistivity is 10 times or more greater than that of a noble metal. The noble metal bypass layer 2 (preferably, of silver) of this high temp. superconductor is turned into alloy with the base metal (preferably Pb, Bi, Ga, Al) of an alloy metal layer 3 through a heat treatment. Before heat treatment, a plurality of methods are exhibited to apply the alloy metal layer 3 to the noble metal bypass layer 2. The layer thickness d1 of the high temp. superconductor 1 is adjusted so as to be smaller than 500 μm. The ratio to d1 of the thickness d2 of the noble metal bypass layer 2 should be adjusted so as to be smaller than 1/5.
LAKNER MARTIN DR
PAUL WILLI DR
