perconducting materials. In 1987, a team headed by physicist Paul Chu of the University of Houston replaced the rare earth lanthanum with an yttrium compound. Chu’s recipe lost resistance at 93 K- well above 77 K, the temperature of liquid nitrogen. This breakthrough was key: Nitrogen is abundant , easier to cool than helium and a fraction of the cost. This promising discovery jolted the scientific and engineering world. Since then, superconductors had become the catchphrase springing loose money for research and fantasies for about “flying” trains that travel 300 miles an hour using magnetic levitation, cheap electricity that can be stored at will, and superefficient motors. However, the problems have been daunting. ceramic materials of high temperature superconductors are often brittle, unpredictable, and fickle. They tend to lose their superconductivity when anything but small currents are applied, and they lack the flexibility to be shaped into useful forms, such as wires or coils.Innovative researches and approaches are under way to overcome these obstacles. MIT scientists are making wires from easily shaped metallics, then oxidizing the wires into superconducting ceramics. At a nearby lab, MIT chemical engineers are exploring the potential of pure carbon materials, known as fullerenes-or buckyballs-to act as high temperature superconductors. Long tubes of carbon atoms conceivably can be made cheaply and in large numbers; such buckytubes would be very strong, and under the right conditions could be made into superconducting wires. Still, after more than half a decade of intensive research, no agreed upon theory exists that explains the behavior of high temperature superconductors, nor is there any consensus about how best to make such materials into everyday products but when success is finally achieved, superconducting wires will be at the heart of so many applications.Modern materials, instead of being us...
