EVIDENCE SUGGESTING SUPERCONDUCTIVITY AT 250-K IN A SEQUENTIALLY DEPOSITED CUPRATE FILM

An artificial cuprate compound belonging to the BiSrCaCuO family with eight adjacent CuO2 layers in each building block was deposited on a s ingle crystal of SrTiO3 by sequentially imposed layer epitaxy. This co mpound undergoes a five order of magnitude resistivity drop with an on set near 280 kelvin and an offset at 250 kelvin. It exhibits a diamagn etic variation of susceptibility and magnetization below 290 kelvin. A dditional observed features, such as strongly nonlinear conductivity, suggests superconductivity as a plausible explanation of the propertie s of this compound.