A promising new class of superconductor materials was described in an article published in May by the Physical Review B. Under normal conditions, the compound zirconium diboride (ZrB2) is not a superconductor. But doctoral candidate Sérgio Renosto, under the advisorship of materials engineer Jefferson Machado, of the University of São Paulo’s Engineering School of Lorena (EEL-USP), discovered that ZrB2 becomes a superconductor that displays extraordinary properties when 0.4% of the zircon is replaced with vanadium atoms. This superconductivity appears at a temperature researchers consider “high,” that is, at −264.3C. What’s most interesting, however, is that the theory that is currently the most accepted in the field fails to account for the energy values of the electrons in the material. “They are due to another mechanism, which has yet to be explained,” says Machado. Another unusual property is the new material’s upper critical magnetic field. The higher its value, the less material is needed to generate high magnetic fields. Its critical field is 16.5 Teslas, greater than the 10 Teslas for the superconductor niobium-titanium alloys used in the coils of magnetic resonance imagining (MRI) machines.
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