Copper oxide, misleading

K later they determined that the drop was a fluke, that subtle shifts in resistance in the contacts between the electrical leads and the sample, and not in the sample itself, were responsible. Sumitomo Electric Industries of Japan came in with 300° K (no confirmation]. In Michigan, researchers at Energy Conversion Devices announced that part of a synthetic material made of fluorine (a highly dangerous yellow gas), yttrium, barium, and copper oxide had superconducted at 45° to 90° F. (The part that super-conducted, it turned out, represented less than 1 percent of the material tested, and the samples were far too small to lose all resistance. It is incredibly difficult to identify the exact portion of any material that shows superconductivity and then produce a pure sample of it.) In New Delhi, at the National Physical Laboratory, scientists saw evidence of superconductivity in material heated to 80° F, but the electrical signals were misleading, an artifact of the measurement process. 

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