Labs hurriedly published their own results on ArXiv, the same server for preprints (papers that haven’t undergone peer review) where the original papers on LK-99 first appeared. Now, a body of evidence has piled up that disproves claims about LK-99. “There is no sign of superconductivity in LK-99 at room temperature,” says one preprint from the CSIR-National Physical Laboratory in India. (That was one of the papers cited by the University of Maryland’s Condensed Matter Theory Center this week when it posted that “the game is over….”) [H]opes that levitation meant that LK-99 is a superconductor were dashed this week after another preprint posed another explanation for why the material might float. The International Center for Quantum Materials in China found evidence that the material is ferromagnetic. That means it can be magnetized and then attracted or repelled by other magnetic materials (iron, for example, is ferromagnetic)…
[T]here are already well over a dozen papers on ArXiv casting doubt on LK-99. “There may be room temperature superconductors to find, but this does not seem to be one,” Chris Grovenor, professor of materials at the University of Oxford and director of the Centre for Applied Superconductivity, tells The Verge in an email.
The Washington Post reports that one of physicists who co-authored the discovery paper “countered in an email that other research groups’ failure to replicate their results are probably because they lack ‘know how’ in developing the sample the same way.”