By Frederick H. Katayama

(FORTUNE Magazine) – Just when the fever over superconductivity had begun to cool, an acrimonious dispute has broken out that has the circuits sizzling. The U.S. Patent and Trademark Office is grappling with the question of who invented the latest copper oxide superconductors, those materials that transmit electricity superefficiently at temperatures as high as -234 degrees Fahrenheit. Potential commercial applications range from ultrafast computers to magnetic trains. Although University of Houston physicist Paul Chu grabbed the headlines, the University of Alabama in Huntsville contends that its former researcher and Chu's collaborator, M. K. Wu, actually invented the yttrium barium copper oxide superconductor in Huntsville and then replicated the experiment in Houston. Says Alabama's general counsel, Robert Potts: ''Wu discovered it in our lab on our campus.'' Houston's lawyer, Scott Chafin, charged: ''Dr. Chu suggested which materials and systems to research and test. Wu might not have been involved in superconductors if he hadn't been a student of Dr. Chu's.'' Meanwhile, IBM insists that all breakthroughs are based on the ''fundamental, pioneering discovery'' of its scientists J. Georg Bednorz and K. Alex Muller, who achieved superconductivity at -459 degrees Fahrenheit with lanthanum barium copper oxide. Big Blue's case is not hurt by the fact that the pair won the 1987 Nobel Prize for their work. The irony is that patents in the U.S. are valid for just 17 years and cannot be renewed. The commercial payoff may come after they expire.F.H.K.