In this preprint, the authors synthesize samples based on the claimed room temperature superconductor LK-99, and observe half-levitation similar to that seen in other recent videos, which has been ascribed to the Meissner Effect (a signature of superconductivity).
However, they performed a careful magnetization measurement and found that the sample is ferromagnetic. They also did a resistance measurement on a larger sample, and found that the majority of the material is a semiconductor. This points to a simpler explanation for the half-levitation phenomenon: it is a consequence of ferromagnetism (+ mechanical effects due to friction and sample shape), rather than the Meissner Effect.
Unless someone can demonstrate full levitation or better resistivity data for LK-99, this is arguably fatal for the claims of room temperature superconductivity.
I tapped out after high school physics and college organic chem, so have almost zero understanding of what’s at work here, but why wouldn’t the original authors have thought to test for ferromagnetism?
Motivated reasoning effects everyone. Even scientists can see what they want to see over what is. One of many reasons peer review is an important part of the process.
